Addictinggames - A variety of free online games
Alfy.com - Fun online games
Coffee Break Arcade - Free internet games directory
Combatgrounds.com - A text-based strategy game to dominate the battlefield through words and strength
Cool Quiz - The world's largest trivia site
Cybertown - Civilization for the virtual age
Escape - Very simple game
Gaia Online - A whole new world of cool new places and interesting characters
Game House - A variety of games; some are free trials of full versions.
Jigzone - Hundreds of online photo jigsaw puzzles.
Joseph Wu's Origami Page - All things origami
Miniclip - Variety of games
Mr. Picassohead - For the artist in you
Neopets - Create your own virtual pet
Runescape - Massive multiplayer online role-playing game
Shockwave.com - Play Flash versions of arcade and other games
Space4k.com - A strategic simulation game to conquer the universe
Ultimate Arcade - Tons of free games
Yahoo! Games - Many different categories of games, and no pop-up ads.