Games For Windows Deal of the Week is World Of Goo for £3.75 or 400msp instead of £14.99
Which is a bargain for a brilliant game. Has been cheaper on steam (Currently £6.99 on Steam) but this is a good price at the moment PLUS for the achievement whores out there - this does have achievements.
Will most likely get voted cold due to Games For Windows bit, but I have never had a problem with GFWL so wanted to share.
EDIT: For some reason it prefers to be launched through the GFWL program on my system (win 7)