Before going to Las Vegas, make sure that you have confirmed your reservation at the hotel of your choice, especially during peak season since the hotels tend to run out of rooms faster, especially the cheaper priced ones.
If ever you find yourself stranded, or without a room reservation, there are other options available such as motels and lodges in the outskirts of the city as well as the bed-and-breakfast. The Hotels in Vegas are such a sight to see since they are replicas of different famous places in history, such as Excalibur Hotel and Casino, with an ambience reminiscent of the medieval times.