Some simple puzzle game would be great. What about a conversion of Zoo Keeper or Bejeweled? I love those two. ALSO: Drop7 for iOS is a cool game!
I'd help you with an y of tehse in graphiocs and/or music if you want
Tetrios Bombliss is also very cool, or a tetris with all the features of the Tetris Online you have on Wii, for example.