XKCD author Randall Munroe appears to have left a neat little cryptographic puzzle for Reddit users in his new book. They're trying to decipher it.
posted by zarq on Sep 21, 2009 - 44 comments

In the spirit of Friday being game day, I give you Broken Picture Telephone; a pictoral version of the classic game of telephone (also known as Chinese Whispers.) Previously on MeFi.
posted by ob on Mar 13, 2009 - 180 comments

Open Doors - a puzzle game.
posted by nthdegx on Jul 15, 2008 - 10 comments

Fun and games with mathematics and mathematical puzzles (e.g. heart basket, Rubik's Cube, Rubik's Magic, hypercubes, and more) in both English and (with yet more content in) German.
posted by Blazecock Pileon on Feb 18, 2008 - 6 comments

Use everyone's logic and vocabulary skills to figure out what the secret word is.
posted by Blazecock Pileon on Jul 20, 2007 - 27 comments

Happy X-mas miniGROW! The latest puzzle in Eyemaze's GROW series. Previous GROW games discussed here, here, and here. [flash] [via jay is games]
posted by brain_drain on Dec 17, 2005 - 28 comments

Japanese Flash logic test
Get the family from one side of the river, to the other. [more inside]
posted by plemeljr on Apr 8, 2004 - 28 comments