Did you know there's an AJAX implementation of nethack? It seems to be pretty full-featured -- not a rouge-like light, supporting every option that the normal version does, right down to tiles. For traditionalists, there's also the internet nethack server known as NAO, where you can mingle with and watch other players struggle through the Dungeons of Doom and lose time in a stunning amount of trivia and statistics. To extend your chances of success you might also want to visit wikihack, which will certainly spoil your experience, detailing the tiniest details and tactics of the game.
posted by boo_radley on Jun 18, 2009 - 86 comments

The Tombs of Asciiroth : A puzzle/adventure game you can play in your browser
posted by boo_radley on Aug 8, 2008 - 13 comments

Ajax your chess experience up with 64squar.es.
posted by boo_radley on Jul 12, 2007 - 23 comments

Vox Imperium A pretty deep web based civilization game.
posted by boo_radley on Feb 26, 2007 - 20 comments