I've a friend just in love with World of Goo. I find it rather uninteresting, but he love it so much that I think I must try it soon or later.
What is the game about?

Quake (and the mission packs: Scourge of Armagon and Dissolution of Eternity), Quake 2, Unreal (and the mission pack: Return to Na Pali), Unreal 2: The Awakening, and replays of Max Payne and Max Payne 2: The Fall of M.P.
Haven't really played too much since mid-January. In the middle of slow games of Dead Space, Descent, Rainbow Six Vegas 2 (which, to be honest, is so bad I might not even bother finishing it), Heretic, Mount & Blade, Jagged Alliance 2, Kingpin, and whatever the hell else.

It's basically a puzzle/engineering game. You have to use the available resources (goo balls that act in different ways) to build a structure that will allow you to get a certain number of good balls from one location to the next.
There's a bit of an odd story to it a well, and there's also the OCD challenge (you try to get the maximum possible number of goo balls to the new location).
If you like that style of game, it's a fantastic game and well worth the money.

Unreal is done!

The evils of a society that places monetary value over artistic beauty.
Or as the developers put it, "World of Goo is just a silly physics game. There were no subversive themes that snuck past the ratings boards."
(Source) http://thereticule.com/2008/12/24/2d-boy-interview-part-one/
In any case the game is a whole lot of fun and the most joyously gleeful I've felt playing a game in years. For $20 it's well worth the price.

Jagged Alliance
Jagged Alliance 2 Renegade Republic
Played some poker, other card games and RtCW ET as well.

Agreed.
I also can't quite shake the feeling that I should be allowed to see more of the game world, I keep on scrolling my mouse wheel thinking I've zoomed in, then remembering that it just doesn't go any further out. That was a pet hate of mine with CnC3 as well. Must be a way of changing that somehow.

The Darkness
Army of Two
Shogo
Prince of Persia (08)
Command & Conquer Red Alert 3
Currently playing:
Fable 2
Dawn of War: Winter Assault

+Bloboats

Dead Space
Tomb Raider: Underworld
Mirror's Edge
Prince of Persia
Chrono Trigger

well, i finished it yesterday, but i didn't have time to post...

I just finish Descent 3
The game is good exept the end... there is no end...

update completed.

Mirror's Edge.
That's about it though, I prefer the more open-ended games, so I end up having 40+ hours in them without finishing (Fallout 3 I'm looking at you).