Vegas.
What a cool place that is!
While you're there make sure you pay a visit to the Sahara, they have a track there you can take a few different cars out in, never managed it last time I was out there a few months back as I was ill, will definitely do it next time though!
Also, this is off topic, but make sure you check out the Foundation Room at Mandalay Bay - it's a club / lounge bar open to the public only on a Monday evening, but has the best view of Vegas, better than both that from the Voodoo Lounge at Rio and Ghost Bar at the Palms.
There's a great go karting place as well down near the Rio, we had great fun there.
I love the place, been loads now, nowhere else like it in the world!
If you've got your license with you there are places on the strip that you can just walk into and rent from, they have 350's and Corvettes just lined up waiting for you. If you're feeling lucky go and see if you can take one of the Ferraris for a test drive from the Ferrari dealership in the Wynn. Oh and check the nightclub out there, beautiful view of the waterfall there!