Electronic Arts just came out with Real Racing 3 for iOS, and its actually a lot of fun on the iPad. (It can be played on the iPhone, but the smaller screen is frustrating.) The car simulation is way better than you'd expect, and the races are against real people on real tracks. It uses Time Shifted Multiplayer, where you don't actually have to be in the race at the same time to race against someone. I don't know how they implemented TSM, as it certainly feels as if I'm racing against real people.
http://www.maclife.com/article/reviews/ ... g_3_reviewThe major downside is the controls-- you can't hook a wheel and pedals to it. I use the iPad's tilt to control steering, right thumb for accelerator and left thumb for brake. There's no pressure feedback like on a real pedal, so it takes some getting used to, but you tap more for more pressure on the gas, etc, and the shifting is automatic as well. They tried to make it easy for novices by providing a lot of auto car control, but that's easily turned off.
The game is free, although, you can pay money to buy or upgrade cars. If you win races, you win cash, and can use that, otherwise you've gotta pay up. I was able to win enough to buy the cars I wanted, but eventually ponied up $5 since that seemed fair for a game I'm enjoying.
You can race against friends, either through Facebook or Apple's gamecenter, so if you want to race, contact me on the Gamecenter at "czei", or friend me on Facebook.