5 unusual games to make you think

Lately I've been plauing a bunch of games. Most of them are the typical "best of the moment" ones: GTA IV, Fallout 3, Left 4 Dead, Gears of War 2... But also, both from friend advices and from trying the demos, I'm playing a few quite interesting and unusual games, and as not everything is coding, here they are for those who love playing too:

• World of Goo: A perfect combination of fresh logic game with cute graphics and sounds. Yoo have to join "goos" (sticky balls of different types) to reach an exit pipe, with dozens of levels and increasing difficulty.
  
• Crayon Physics Deluxe: Another fresh idea: Painting boxes, circles, ropes you have to make a red ball touch a star. All with incredible physics (that allow a lot of different ways of finishing each level) and nice (but simple) graphics. An interesting feature is that it is done with TabletPCs in mind.
  
• Defense Grid: It would look at first as a simple commercial Tower Defense game, but I can't remember the last time that I played for 7 hours non-stop a game, and it happened with this one. Nice graphics, well designed levels, adjusted difficulty and "challenge modes" provide lots of hours.
  
• Patapon: This is the most strange game of the list. A mixture of 2D real-time strategy and rhythm matching, with some RPG elements. Has great Flash-like graphics, tiny (it's for the PSP) but full of detail. Beware, after playing it for a while, you will start singing the drum commands (pata-pata-pata-pon!).
  The only failure of the game is the apparent lack of variety in those commands (but I have only played a few levels and discovered 3 drums yet).
  
• Defcon: Did you ever wished to see a nuclear war strategy game like the one from WarGames film? Defcon is your dream come true. And now with a new bot API to create true computer wars.
  

Except for Patapon (which I'm not sure), all the four others come from indie game companies, so my message is: Triple-AAA games look gorgeous and "almost everybody plays them", but if you want really fresh or addicting games, look out for indie ones ;)