Here is the Nethack server at alt.org, Telnet link,  Java client, Flash client.  Here is a list of most of the ways to die in the game (dates back to 3.1.3).  And here are a lot of Nethack spoilers.
posted by JHarris on Dec 20, 2011 - 38 comments

Twenty years ago today, the gaming world saw the launch of a truly landmark title: Sonic the Hedgehog. Developed as a vehicle for a new Sega mascot, the fluid, vibrant, cheery-tuned wonderland swiftly became the company's flagship product, inspiring over the ensuing decades an increasingly convoluted universe of TV shows, comic books, and dozens of games on a variety of systems (all documented in this frighteningly comprehensive TVTropes portal). And while in recent years the series has turned out more and more mediocre 3D and RPG efforts, the original games remain crown jewels of the 16-bit era. So why not kick off this anniversary by replaying the titles that started it all for free in your browser: Sonic the Hedgehog (1991), Sonic the Hedgehog 2 (1992), Sonic the Hedgehog 3 (1994), Sonic & Knuckles (1994). Or click inside for music, remakes, and other fun stuff! [more inside]
posted by Rhaomi on Jun 23, 2011 - 71 comments

Hanafuda (Koi Koi) is a flash game that plays with the hanafuda deck of cards. (As a trivia side note, hanafuda cards were the beginning of Nintendo.) Once you're familiar with the deck, you can play Minhato, a java game that uses the same cards. [more inside]
posted by klangklangston on Apr 16, 2010 - 19 comments

An Informal Catalog of Slit-Scan Video Artworks and References
"Slitscan^w imaging techniques are used to create static images of time-based phenomena. In traditional film photography, slit scan images are created by exposing film as it slides past a slit-shaped aperture. In the digital realm, thin slices are extracted from a sequence of video frames, and concatenated into a new image." [via] [more inside]
posted by carsonb on Mar 12, 2009 - 11 comments

Annoying Software : A Rogue's Gallery. (single-page version). Software that makes us hate the internet and wish it had never been invented. High on their list : Adobe Reader, Java, RealPlayer, and Flash. [more inside]
posted by Afroblanco on May 20, 2008 - 111 comments

Double Wires (flash) Point and click to shoot out grapples or webs. Move to the right to advance your score.
War of the Hell (java) Get the stick figures to climb your rope and then carefully fling them skyward to 'Heaven'.
(Via d_of_i's always unique DOFI-BLOG, creator of Cat Sledding and the mesmerising Sand Sand Sand.) (Third in a continuing series of physics games posts.)
posted by loquacious on Oct 23, 2006 - 13 comments

Dreamlines
posted by Tlogmer on Nov 23, 2005 - 26 comments

S u m e a features some amazing ways to use Java and Flash on the web. The best thing about the whole site is how fast all the 'applets' load on my 56k modem.
posted by Mark on Apr 18, 2000 - 4 comments