Portal [The Orange Box](PS3, Xbox 360, PC, 2007)
OK, so the cake was a lie. But as if Portal wasn't already awesome enough, completion yeilded a superb song sung by GLaDOS - the sinister computer system that... well, play the game and find out. We've stopped the song short here so as not to give away a plot spoiler. But what an awesome and funnyoffering it is - just listen to the words.
Above:There's no use cryingover every mistake - just keep ontrying till you run out of cake