Tower Bloxx Deluxe $2.99

This game was my savior on a 10 hour car ride. It's very easy to play, but very hard to excel at. With multiple forms of game play and numerous achievements to unlock, this game will keep you occupied for hours (which in itself is an achievement in the game). I was a little disapointed when I ran out of things to do in the game, but it was still worth upgrading from the lite version.