This app was mentioned in 3 comments, with an average of 13.00 upvotes
Not sure if this is just available in America, but the MyVegas App for your phone and/or game on Facebook is a good way to get some free perks on your next trip to Las Vegas. You can play slot games for free and earn coins/points to cash in for free food, shows, hotel rooms, etc...
Edit: formatting
Correct. Some companies also skirt that second part by letting you exchange the virtual currency for real life deals like hotels, trips, etc...
See: MyVegas