I disagree. Do as much as you can. You will get plenty of rest when you're dead .

>>>what are the "must do's" in Vegas now?

You aren't going to be there very long but here are my standard suggestions from another tourist who doesn't get there very often....

1) If you haven't already done it, take a Hoover Damn - Grand Canyon tour.

2) If you are into thrills, do the rides on top of the Stratosphere (even if you are not into thrills, there is no better view of Las Vegas than from the top of the Stratosphere and having dinner there is really something).

3) If you are into romance, dinner and a Gondala ride at the Venetian or dinner and watch the Bellagio fountains from atop the Paris tower (my wife just loves doing both).

4) All of the shows in Vegas are fabulous. Your choice will be based more on whether you like magic, comedy, song and dance, etc.

If you are doing a chip run on Freemont Street at night, you will get a real kick out of it.

Merry Christmas and have a great time!!