Take a trip to the Hoover Dam and/or the Grand Canyon. Vegas alone can get on your nerves, especially if you're not a heavy gambler.
Look for a show, there are shows for all budgets and tastes.
If you like shopping, that's the place to be.
The Excalibur Hotel has a Renaissance show and family friendly arcades and similar things as well as entertainment for adults.
Hotels provide good spas with amenities, such as therapeutic, professional massages.
And of course, if you find family friendly entertainment boring, there are reasons why they call it Sin City. Check the listings.
Just walking around the strip is fun too.