Las Vegas is the most populous city in the state of Nevada, It's internationally renowned for gambling, shopping and entertainment. There's a large number of casino resorts and associated entertainment. The city's tolerance for various forms of "adult entertainment" earned it the title of Sin City, with the tagline of "What happens in Vegas, stays in Vegas."
This image has made Las Vegas a popular setting for films and TV programs. However, the city of Las Vegas is never fully portrayed, instead anything set in the city of Las Vegas usually takes place on the strip. The strip is a long avenue with giant casinos on each side. This is where all the gambling and parties take place. Each casino doubles as a resort and usually has a theme attached to it. The Luxor is a giant pyramid while the Bellagio features a recreation of Venice. Each casino also has a shopping mall which usually features luxury shops such as Tiffany's. Each casino links to the next so the consumer is constantly shopping and looking at products. Some casinos also have attractions such as shows (Celine Dion at Caesar's Palace).
The most important part of Las Vegas is its casinos. Each casino is built pretty much the same. They are built in a manner that encourages gambling. There are no windows in the casinos and the air is oxygenated. Also there are no clocks. This helps gamblers lose track of time and also stay awake. The carpeting is also there to promote gambling. If you stare at the carpet you will notice that there is a sort of drawn out hallway. If you are underaged or do not wish to gamble, you are required to stay in said hallway.
Las Vegas is featured in many games. Usually these games take place on the strip. However, these games usually don't use the names of the casinos on the strip, making up their own casinos, sometimes to parody the real casinos (the Fellatio in Duke Nukem Forever). Las Vegas is the setting of the often delayed Duke Nukem Forever.