Peggle Extreme
This came with my Orange Box for ... some ... reason. The backgrounds and some flavor graphics and sound bits have been taken from Valve's closet, but the gameplay is - as far as I understand - the same as traditional "Peggle," whatever the hell that is. It's a PopCap game, and you should pretty much know what to expect from it.
Progress: Gave Up -- Got to level ... 5? Who cares