I have been playing from the beginning when they actually had great rewards.
Off the top of my head
2 free nights at Aria and also Mandalay. ...weekend consecutive nights. Also free weekend nights at MC, Luxor, MGM, several $150 steak dinners at Excalibur (not bogo or minimum spending). Premium tix to Ka, Zarkana, Love. Other buffets, meals, free play etc.
Gradually those rewards started disappearing. You could even choose Bellagio fountain songs or get complete wedding package.
Now all you get is a free pizza topping or 25%off rack rate midweek off season.
