There are three treasures hidden in Vegas itself - "Feeling Lucky" and "Triangle Building" will no doubt be easy to find. "Crystal Clear" might take a bit longer.
You'll need a stamp and/or a pen; and if you want to keep part of the treasure you should bring your own piece of paper or notebook.
http://www.letterboxing.org/BoxByRegion.as...uthern%20Nevada
This is something very old and cool that's been going on in Europe for nearly 200 years, it's new to the states but there are treasures everywhere. Be sure to check the map on the site for your own state to see if there are any near where you live.
If you're driving to Vegas, you could even see what treasures you can find along your route!