I found this game on Steam last night.
It's a really cool racing game. Racing against other cars is kind of different. They're "ghosts" per say. You can go through them, but you're all on the same track. So basically it's who can get the fastest time. Still, it's a lot of fun. It's got incredible graphics and arcade style gameplay. And best of all, it's FREE.
There's single player and multi player.
Total customization too. You can make your own tracks, paint your car exactly how you want.
The tracks are awesome. They have enormous jumps, loops, etc... And you can use them all in the track editor.
I got it off Steam, but here's the website for it.
http://www.trackmania.com/en/