Any game that you loved to death that either; A) No one else knew existed, or B) Simply wasn't covered in mainstream media.
I cast my vote automatically for Spongebob: Battle for Bikini Bottom. How someone took Spongebob, just ol' Spongebob, a fairly funny kid's show but just Spongebob, and turned into a balls out awesome action-adventure (I think?) game.
The premise was ingenious and simple. Plankton makes robots to take over Krusty Krab, unfortunately created, and left lever turned to "Don't Obey", and they start running rampant. Spongebob and Patrick wanted real robots to play with, so they put a toy one in Pat's conch and made a wish. The next day, Spongebob thinks it's all his fault, so he goes out with a bubble wand and some help from the people around him to collect golden spatulas, for no thoroughly explained reason, to unlock more levels to finally get into the Chum Bucket and save the day.
The game is awesome, and more often than not, pretty damn funny. The game mechanics are too awesome. Anyone else love this game? I gush over it, it's fan-fuckin'-tastic.
Your turn.