Developer The Binary Mill has been trying a number of different approaches on iOS (including the Penny Arcade-approved Decide-o-Tron game recommendation app), but Mini Motor Racing HD is the company's most solid release yet, in my estimation. It's a top-down mini car-racing game with a pretty exceptional amount of polish. The controls are well-made, there's a lot of fun progression options for a number of different cars, and the cars themselves are really well-rendered, so much so that on the iPad especially they really do look like real little toys.
The game only has one option for multiplayer, you can only play with one other player, either