I've got to say.. I have done some pretty cool/adrenaline-type/adventure stuffs and while this doesn't beat skydiving over Lake Wanaka or Bungy Jumping over the Shotover river in Queenstown; it is not trailing far behind.
I booked a Rookie Tour with the guys at the Richard Petty Driving Experience and my mates got himself a ride-along with one of their drivers; and we both loved it. It was great fun.
The Rookie Tour is basically you at the wheel of a 600 HP Nascar Race car w/ an experienced driver in the seat next to you and he guides and makes sure that you don't kill yourself during the 8 laps that you're allowed to do at the Las Vegas Motor Speedway.
I really liked the whole experience - they pick you up at a pre-determined location on the strip, drive you out to their shop (where you learn a bit about their story and how they do things & you can also get photos with some of their really cool cars) then to the Vegas Speedway, get you geared up and show you a safety video. Then you head to the track and wait your turn to race. There are some really cool cars along the track where you can get shots.... Bumblebee was there!
The only letdown is that you are only allowed to do 8 laps, which goes really really fast! It's quite pricey (I paid about $650) but worth doing if you in Vegas - the guys are very nice and they make sure that you have a great time!