People come to Vegas from all over the United States and the world, and there is no better place to watch them than on the Strip. Wait until the sun goes down and the lights come on. There aren't many places to sit outside on the Strip, but there are benches in front of and around the fountain at the Bellagio. There are several places in front of the Bellagio to get a drink such as a refreshing frozen lemonade or a more adult beverage while you watch. Try to pick out the locals from the tourists. Everyone else will be watching the fountain, so you will have a great opportunity to see people's faces and reactions to the spectacle.
Once you've taken in the people, take in the Strip itself. The Mirage's volcano light and water show is just south of the Bellagio and is a great next stop. You can also cross the street on one of the skyways and visit the Miracle Mile shopping center at Planet Hollywood. Some of the best hotels to explore are the themed ones, with their painstakingly created environments, such as the Excalibur, the Luxor, Treasure Island and Caesar's Palace.
If you love to get your adrenaline pumping, start at the north end of the Strip, where the Stratosphere Hotel and Casino offers the tallest observation deck in the world and features three exciting rides, one of which throws you straight up into the air, while the other two suspend you out over the Strip, almost 1,000 feet below. Circus Circus is just to the south, and features an indoor carnival, complete with midway and roller coaster. Circus Circus also offers bungee jumping. And just across the street behind the Riviera, you can find indoor skydiving.
Finish off your solo time in Vegas with some decadent pampering at an area spa. Many of the featured casinos on the Strip offer spa services, but some of the most exclusive are at the Bellagio and the Wynn. Reward yourself for being such good company by spending some time soaking, getting a massage or skin treatment and getting wrapped, mudded and powdered.
