I just returned from Las Vegas and Mandalay Bay. Wow!  The hotel is HUGE and you literally don't ever have to leave as everything you need to do or see is there.  I didn't leave the property for 2 days!  The 1st night there, I went to see the live show Mama Mia which was great; the actors were superb & gave a stellar performance.  I was on the 7th row right in the middle and in front of the stage; great seats!  Also, the exhibit Shark Reef is there and is sure to please everyone.  The casino is right in the center of the hotel so you have to walk through it (smart!) to go to the restaurants or exhibits; it always seemed to be bustling with activity night & day.  Mandalay Bay has a great pool & lazy river which were closed due to the season; it will reopen in the spring '09.  The full service spa was also wonderful!  There is a complimentary monorail that takes you to the Luxor and Excalibur hotels which is very convenient.  I did see the choregraphed fountain show in front of the Bellagio Hotel; it is spectacular & happens every 30 minutes.  I will definately be back to see more of Vegas!