You may never have actually experienced this, but here in Los Angeles, every time we head out on the freeways, we face a dreaded threat: the motorcyclist. Not that I actually have anything against these guys (I'm sure they're very nice), but in LA, I've found that they tend to have a set of rules outside of the normal traffic -- even when you're parked on the 405 at a standstill thanks to a traffic jam, the guys on motorcycles are somehow able to split lanes, flying down the dotted line in between two long backups of cars.
And that's what Lane Splitter is all about -- you play a motorcyclist rushing down a freeway, cutting in between various cars as you speed on. It's generally a Canabalt-style running game, but using the accelerometer to steer provides a fun driving twist to the game, and pulling a wheelie on your motorcycle can add up some extra points as well.
Unfortunately, there's no Game Center integration, though there are global leaderboards, and an update is promised in the future (though it hasn't shown up since December). But Lane Splitter has another bonus going for it on this Friday: it's currently completely free for both iPad and iPhone. If you're down to do some traffic weaving this weekend, give it a look.