Plan a tour to Hoover Dam. Leave early in the morning, returning to Las Vegas after lunch via Valley of Fire State Park, stopping at the Lost City Museum in Overton en route. Alternatively, you can rest up by spending the day by the hotel pool or going to the hotel spa. At night, presumably refreshed and toxins purged, hit the casinos and/or catch another show. If you aren't tired of magic, Lance Burton is a wonderful show for a reasonable price, or there is the arty weirdness of the Blue Man Group at The Venetian, or Jubilee!, if your trip won't be complete without a topless revue. You can also feast at dinner since you certainly haven't tried all there is. There is some great work being done by restaurants not associated with brand-name chefs, such as Rosemary's, Alizé, Hannah's, and Andre's.
As you plan any additional days, consider excursions to other nearby attractions such as Lake Mead, the Grand Canyon, or even Area 51. Inquire about interesting possibilities at your hotel's tour desk.
