I know you all have atleast one. Post them here so I we all can enjoy. Here are mine
http://www.armorgames.com/games/portaltheflashversion_game.html - Portal
http://www.nekogames.jp/mt/2008/01/cursor10.html - Cursor 10
http://amanita-design.net/samorost-2/ - Samorost 2
http://www.albinoblacksheep.com/games/bloxorz - Bloxorz