If you haven't been to Vegas in awhile, Downtown has really changed. It is now home to some amazing restaurants and bars (Jennifer loves Commonwealth), Container Park as well as the famous Fremont Street Experience. The people watching is to die for.
The best way to see The Strip is on foot so bring comfortable walking shoes! The Bellagio Fountains, Bellagio Conservatory, Venetian gondolas and the Mirage volcanoes are just some of the one of a kind sights to see.
Red Rock Canyon has some beautiful views and laid back hiking trails as well as more advanced one's.
For those who want some crisp Spring mountain air, a ride up to Mount Charleston isn't far away (about 1 hour). Have a drink at the lodge, explore nature and take a break from casino scene.