I have been to Vegas for Christmas/New Years and there is plenty to do. You don't have to be over 21 to go into a casino in Vegas but you do need to be 21 to gamble. Nobody will stop him going in, seeing the shows, eating in the restaurants, checking out the action etc. But he can't sit down at the tables. People watching is excellent though so he will enjoy. I have stayed at the Wynn (which I didn't like very much) and have stayed at the Landmark MGM (which is fabulous). The Landmark MGM is located at the back of the MGM Grand. Not much at the Landmark for kids though so I would give the Belagio a try (always wanted to stay there). Definitely take a helicopter ride over the Hoover Dam and Grand Canyon (do not take a bus tour - it's too far to go). That's something you'll both remember for the rest of your lives. Don't take the early trip - take the slightly later one as the helicopter will take you back to McLaren via the Strip which will be all lit up at night. Go to one of the Cirque du Soleil shows - my favourite is O (at the Belagio) but Ka (at the MGM) is also good. Take the tour of the Neon Graveyard. This place is run by volunteers and you need to contact them to book in as the tours are very small and don't run often. It's really good. Vegas is a town with no history because when the hotels start to look old they tear them down and start again. The Neon Graveyard is the only place in Vegas with anything old in it - you get to see all the original old Vegas signs. Plus, they found a dead body there once in CSI. I can't recommend it highly enough.