We got passes to Madame Tussauds as part of our package from the Venetian. This "interactive" wax museum is located on The Venetian property and ticket prices are a little more costly than one might think they would be. Also, the museum could be bigger. We made it through the whole thing in about 30 minutes.
There are a variety of celebrity wax sculptures and you can touch and pose with all of them for pictures. There are no barriers seperating you from the figures.
Look for a coupon before going (or find a package that offers admission to a group of vegas attractions for a discount) and don't forget your camera!