Walter Randelshofer's Pretty Patterns collection (for Rubik's cubes up to 5x5x5) is one of the nicest twisty puzzle sites going. It's based on his CubeTwister software, which you can download (including a lovely OS X standalone). If you really want a treasure trove of twisty polyhedra, check out gelatinBrain's enormous collection of java applets (which unfortunately don't do so well on macs). Are those things even physically possible? Really? Mini bonus: Randelshofer also hosts an archive of fondly-remembered Amiga animations.
posted on Mar 31, 2008 - View this thread

Chess Problems has hundreds of problems in six difficulty classes from novice to fiendish [java]
posted on Feb 16, 2008 - View this thread

Created by flash artist and graphic novelist Mateusz Skutnik, Submachine is one of the class acts of the point-and-click Web-game genre. Mesmerizing, layered and absorbing, the latest chapter in the series has just been released.
posted on Feb 1, 2008 - View this thread

A virtually unlimited supply of randomly-generated logic puzzles, in a variety of sizes and difficulties: Nonograms. Slither Link. Nurikabe. Bridges. Light Up.
posted on Nov 28, 2007 - View this thread

Spot the Five Differences. It is fun. [flash]
posted on Oct 10, 2007 - View this thread

Bored on your summer vacation? Well, the US government has lots of fun stuff for kids to do on line. Learn fascinating facts about cows (and agricultural marketing!) from the Department of Agriculture. Take a ride to Money Central Station with the Bureau of Engraving and Printing. If you live in a federally-funded housing project, HUD wants you to learn more about being a good citizen. Want something more action-packed? Help FBI Special Agent Bobby Bureau go undercover, or become one of America's Crypto-Kids at the NSA. Play thrilling puzzle games or visit the world's most secret museum at the CIA. Play more games or become a Disaster Action Kid at FEMA! And no list of government kids' pages would be complete without revisiting the children's art contest from the ATF, which I've linked to before...
posted on Jul 25, 2007 - View this thread

Puzzability is a puzzle writing company created by three former editors of Games Magazine. Start with their puzzle sampler and come back for a set of regularly updated games. Puzzability is also responsible for creating the New York Times' intricately crafted Op-Ed Puzzles. Unlike the Times' daily crosswords, these wonderfully elaborate puzzles are available in a free archive.
posted on Jun 26, 2007 - View this thread

Rush Hour is a sliding block puzzle invented by Nob Yoshigahara and manufactured by ThinkFun. The goal of the game is to get the red car out of a six-by-six gridlock of vehicles by moving the other vehicles out of its way (youtoob). There are several online versions in Java/Flash (bottom of link)- my favorite has the first 2 complete sets from the board game. It's a gentle warm-up for your brain.
posted on Jan 25, 2007 - View this thread

Since Wordplay has come out, crossword puzzles have been on the rise. If you want to join in on the fun, read this primer by Will Shortz to get started, then download Across Lite, head to Cruciverb, and do free puzzles in the right-hand sidebar. Will Johnston's page contains a huge repository of Across Lite puzzles. If you get stuck, can't figure out why an entry is correct, or just want to chat about a grid's brilliant construction, try reading the crossword blogs. The best two are Diary of a Crossword Fiend and Rex Parker Does the New York Times Crossword Puzzle. (Caution! Spoilers abound!) And, if you want to try your hand at constructing some crosswords of your own (submission guidelines for various papers here), Crossword Compiler is an outstanding piece of software. [Via this AskMetafilter question]
posted on Jan 22, 2007 - View this thread

AcceleRacers: Track Mod is a fun little Pipe-Dream-esque Flash game in which your object is to manipulate sections of track in order to get each of your six racecars to the finish line inside the time limit. Gets a lot harder as you go up in levels and more obstacles are added. Yes, it is a HotWheels game.
posted on Jul 19, 2006 - View this thread

"King Anfortas currently owns this magic stone, schmooze him, take him surprise, how ever you will get it, but bring me this stone! As award I promise you my daughter and a place on the crown!" -- The Mystery of Castle Wildenburg, a slightly goofily-translated game that combines point-&-click with classic text adventure gameplay, and photos of the lovely German countryside. Read the "Prehistory," mouseover everything, save often (though you lose your accumulated points on loading a saved game), and be careful not to die of thirst.
posted on Jul 17, 2006 - View this thread

Tangram House
posted on Jun 17, 2006 - View this thread

Cityscape. (Flash game) Build a city with 18 available components. The order in which those components are employed determines how they'll interact and how far the city will develop. There's one correct order that will score the full amount of points. (via)
posted on Mar 10, 2006 - View this thread

More point-n-click Flash puzzles, this time in a series: Escape to Obion, episodes one, two, three, and four.
posted on Feb 27, 2006 - View this thread

Inspector Wombat, a point-and-click Flash puzzle game somewhat clumsily translated from the German. Inspector Wombat has a seemingly-bottomless sack in which to store all the random crap he picks up, like banana peels, his lady friend's stereo system (dude, she's standing right there. Ever try asking?), and tasty foodstuffs somebody left in the street. Your object is twofold: Find and apprehend the kooky blackmailer who's messing with the museum director, and fix the museum's paintings which have mysteriously gone all wonky (hint: it's because of evil, unhappy bacteria).
posted on Feb 25, 2006 - View this thread

Tetrod is a jigsaw puzzle and a four-sided domino game mixed together. -- Java puzzle game; choose 3x4, 4x4, 5x4, or 5x5.
posted on Feb 24, 2006 - View this thread

Flea Circus! It's just like Lemmings! Only tinier! And faster! And you can only make three moves: Block, ramp, and other ramp! (java)
posted on Feb 17, 2006 - View this thread

Attic Escape is another little "escape the locked room" Flash game along the lines of Crimson Room, Viridian Room, White Chamber, The Doors, and MOTAS. Also by the creator of Attic Escape are Nightmare Escape and, er, Cannibal Escape (which is worth clicking for the lovely, cello-heavy strings music if nothing else). Click everywhere in Attic Escape; important items are hidden behind, above, and under everything.
posted on Feb 4, 2006 - View this thread

A Case of the Crabs, and its sequel, The Goat in the Grey Fedora, are a couple of point-and-click black-and-white Flash games that parody the old Sam Spade-type noir films. You are Nick Bounty, private detective, and it's up to you to solve the mysteries of the counterfeit crabs and the miniature goat statue, respectively. Very, very jokey; guaranteed to induce eyerolling. Look at everything, talk to everyone, and pick up everything that's not nailed down. Hints are available, but they're crammed with jokes too.
posted on Jan 29, 2006 - View this thread

The Flowering Nose in Slugland adventure game. As a goblin with a flower for a nose, your ultimate goal is to find the lost sprout. Defeat enemies by throwing flowers at them; power up with hearts; teleport from level to level with such esoteric trinkets as donuts and cherries. (Java.)
posted on Jan 27, 2006 - View this thread

"You awaken from an uneasy dream.You are in a small, bare apartment. You are alone. You have no idea how you got there. You don’t even know who you are." Fans of Franz Kafka may appreciate Kafkamesto, a bleak and bizarre point-and-click Flash game.
posted on Jan 20, 2006 - View this thread

Cubeoban -- Arrange the colored blocks so that they cover the colored dots. (Flash.)
posted on Jan 19, 2006 - View this thread

Yet another Flash puzzle game: Shift. Very beautiful, with low-key music.
posted on Jan 10, 2006 - View this thread

Things Came Up To My Brain...Museum? A little Flash game, from the same Samorostian/Goldbergian mind that brought us Find The Treasure. Warning: There doesn't appear to be any way to toggle the sound off.
posted on Jan 9, 2006 - View this thread

Fsaturday Flash Fun: CryptoQuote. Other word games featured at East of the Web are the Tetris-like PopWord (and its multiplayer companion [beginner and advanced, respectively]), the MasterMind-like CodeWord, and the vaguely Scrabble-ish 8 Letters in Search of a Word.
posted on Jan 7, 2006 - View this thread

Friday Java Fun - Junk's Hanoi, a cool puzzle for this lovely Festivus.
posted on Dec 23, 2005 - View this thread

Memory - 36 cards. Turn two over. If the pictures match, both get eliminated. Else turn them back and select another two. Repeat till field is cleared. Post the number of moves you took. [via]
posted on Nov 13, 2005 - View this thread

What do you get when you mix a fiendishly difficult and addictive puzzle game with the feel of a hack & slash RPG set in a cartoonish, slightly tongue-in-cheek fantasy world? That would be Deadly Rooms of Death (DROD for short). The game is freakin' huge, with 25 levels filled with unique rooms, and it also happens to be free.
posted on Sep 22, 2005 - View this thread

Go problems database with a slick web interface. Go is one of the most rewarding games I've ever played. You can play games at ItsYourTurn.com, who also have a nice rule summary.
posted on Jun 1, 2005 - View this thread

The puzzle that ate the world?! It's called Su Doku. It came from Japan. It's deceptively simple, but a brief tutorial reveals hidden depths. It's spreading like gangbusters through the puzzle-obsessed British public, where it is making major news and being rapidly added to the country's newspapers. Fortunately, archived puzzles and free software are out there to provide puzzle addicts their latest fix. C'mon... give it a try. It's only *one* little puzzle. (Heh, heh.)
posted on May 10, 2005 - View this thread

Braingle
posted on Mar 16, 2005 - View this thread

Ponder This. 'You are cordially invited to match wits with some of the best minds in IBM Research.' Monthly puzzles, with solutions, going back to 1998.
posted on Mar 7, 2005 - View this thread

Reflex is the game responsible for a significant drop in the scores of my final exams. (Friday Flash)
posted on Dec 17, 2004 - View this thread

Arghhhhh!!! Aghhhhhhhh! Arghhhhhhh!!!

Cheats for PuzzleDonkey4 Available here
posted on Dec 1, 2004 - View this thread

"Sam Loyd's 'Trick Donkeys' is one of the most elegant puzzles ever invented... print out the page and cut the figure into three parts along the solid lines. Now, position the strip onto the other two pieces so that it looks like each jockey is riding a donkey. Folding is not allowed. Don't give up -- the solution is really quite simple!"
posted on Oct 31, 2004 - View this thread

Tuesday Diversion -- puzzling entertainment for those who are having as difficult a time with motivation this Tuesday-after-a-holiday as I am.
posted on Sep 7, 2004 - View this thread

"WARNING!!! The puzzles on this site are very difficult, and most require the use of a good spreadsheet program in order to solve them. It will take many hours, perhaps days, to solve each puzzle..."
posted on Aug 11, 2004 - View this thread

Puzzles.com (Flash)
posted on Aug 7, 2004 - View this thread

Petals Around the Rose This little puzzle took my genius son over an hour to figure out. It took me two seconds. They say the smarter you are the harder it is...shut up.
posted on Jun 4, 2004 - View this thread

Interactive Philosophy Games :: Construct a God, explore your morals, take a new look at what it means to be alive, plus Shakespeare vs. Britney Spears. Or, you can just read it for the articles.
posted on May 10, 2004 - View this thread

Riddles and more riddles - Easy Riddles and Ancient Riddles, Math Riddles and Traditional Riddles, Anglo-Saxon Riddles and Lawyer Riddles, Dirty Riddles and Logic Riddles, Medieval Riddles and Awful Riddles. Finally: Ambiguity, Classification and Change: The Function of Riddles.
posted on Oct 14, 2003 - View this thread

Ars Magna hosts The Anagrammy Awards, a monthly anagram competition. This got me thinking that we could "rearrange" the big acronym thread from a few weeks ago so that the first word or phrase of a comment would be an anagram of the last word or phrase of the previous comment. Sort of like this.
posted on Aug 22, 2003 - View this thread

The Elliot Avedon Museum and Archive of Games. Board games from a thirteenth-century 'Book of Games', Inuit games, card games, row games, puzzles, ethnographical papers on games, etc.
A different kind of game at Streetplay - stickball, hopscotch, galleries, and street games worldwide.
posted on Jul 16, 2003 - View this thread

4D rubiks Cube. There's a small (416k) download, but then it's probably the hardest puzzle in the world. It should keep you busy for a few hours.
posted on Jun 9, 2003 - View this thread

Need a job? The winner of the Google Puzzle Contest might recieve a prestigious spot in the Google engineering labs. So whip out all your old Martin Gardner books and get practicing, because the competition is on May 1st (and registration closes today).
posted on May 29, 2003 - View this thread

So What Happened After The Wise Man Discovered He Was Wearing The Red Hat? Don Steinberg's hilarious brainteaser aftermaths inevitably makes one wonder what happens after fairy-tale endings or the punchlines in jokes.
posted on Jan 31, 2003 - View this thread

Puzzle that makes you weep softly and twitch. Cryptic crosswords are mostly unappreciated on US shores, but those who have learned to seek them out have struck upon perhaps the best wordplay puzzles ever. Instead of rewarding a solver's grasp of trivia, cryptics are truly a battle of wits in which each clue is a riddle that plays by a few simple rules. Part of the riddle is a straight definition of the final word; the rest is subtly disguised wordplay. It's hard to know just why these haven't caught on — it may be that the most readily available ones, such as those in Harper's or The Atlantic, are extra-tricky affairs that cater toward expert solvers. But online, there are plenty of puzzles suitable for those interested in giving cryptics a whirl, including this gem, written for a 12-year-old audience.
posted on Jan 27, 2003 - View this thread

Alien Tiles Game. Play the game, then see the scientific papers from the UK and from Rutgers University on the subject. Enjoy.
posted on Nov 11, 2002 - View this thread

Not just a nostalgic trip. The fascinating story of Erno Rubik, inventor of, well take a guess.
posted on Nov 3, 2002 - View this thread

this childs game (java applet) is so complex you could use it to construct a computer. the original paper (postscript), is heavy going - if you're not a compter science student but would like to understand more try this wonderful book by one of the authors (example pictures).
posted on Oct 7, 2002 - View this thread

It starts with Delaware... Over at Google Answers, a Microsoft Games Studio employee has posted a most interesting puzzle to solve. Over the course of the last twenty months a list of states has been gradually revealed by his boss, but under what criteria are they listed? He's giving $200.00 to the winner; just think of what you could buy. The fine folks at the Straight Dope are already on the case. To the Googlemobile! [via Cardhouse]
posted on Aug 22, 2002 - View this thread

New and improved crack! Now with better hypnotics!
posted on Apr 21, 2002 - View this thread

If you're a fan of Interactive Fiction then you'll certainly be familiar with Andrew Plotkin the author of some of the best works in the genre, including Spider in Web and So Far. Only Macintosh users, however, will remember his phenomenol early-90s puzzle game, System's Twilight, "An Abstract Fairytale." I recently played it again, and am astounded that such an early piece of work contains such a fully realized fantasy world (literally, it's abstract) and such goddamn hard puzzles. Download it and experience some gaming history, and a damn good time.
posted on Aug 2, 2001 - View this thread

"Logic Mazes" a.k.a. Theseus and the Minotaur -- Spinnwebe led me to this site, where I spent about four (non-continuous) hours trying to solve the fourteenth maze. Don't follow the link unless you have some time to kill.
posted on Feb 3, 2001 - View this thread

Here's a gift for all. Someone got a deceptively simple card game as a stocking stuffer. Three shapes. Three colors. Three shades. Three different numbers of objects. Put 3 things together that are completely similar or completely different, for all four variables. It's a card game that instantly sucked several of us in and felt like playing Tetris the first time. Go ahead and give it a try (note, I've been playing this for a couple hours today and I could only find 4 of the 6 possible sets).
posted on Dec 25, 2000 - View this thread

among other stuff, the adam clymer fan club brings us: anagrams: george walker bush & gore blew a keg rush, The Dubya Virtual Magnetic Poetry Page, the compassionate conservative problem-solving flow chart, and punch sam donaldson and win $20!
posted on Oct 15, 2000 - View this thread

Chu-Chu! Banzai Shock On! It was Dreamcast game you were sick to death of hearing about, now it's the Shockwave game you can't quit playing. TSUBABABABA!
posted on Mar 23, 2000 - View this thread