ProStreet is the latest installment of the Need for Speed series, and by all accounts it looks to be the most comprehensive one since the franchise started going Underground. This one still has a pseudo-sub-culture bent to it, but at least offers some serious motorsports action, and now you’ll get a chance to try it out for yourself. A demo of the game is now available for Xbox 360 gamers in the Live Marketplace. The demo apparently includes a taste of “grip” racing (called “racing” by you and me) as well as an event they call the Speed Challenge. So, fire up your download queues. Those 650-odd megs aren’t going to install themselves.