If you're itching to try Criterion's Need for Speed: Most Wanted before you buy, today a demo is releasing, so you'll get your chance. It's available on PlayStation Network and Xbox LIVE only -- if you're a 360 owner, hit the source to check for a download (if it not available on either service yet, keep checking back throughout the day).
The demo features the classic Aston Martin V12 Vantage, plus the Porsche 911 Carrera S, Audi R8 GT Spyder, and the Ford Focus RS500 if you can find them; each ride offers different races, challenges, and mods. Autolog 2 can be seen as well, on which you can earn up to 50,000 points which carry over to the full version of the game.
Most Wanted is available now on...everything.