You can enjoy a Las Vegas brunch any day of the week, although the weekend is the place to really experience this middle-of-the-day meal. Since you're in Vegas, you can expect to find plenty of libations to go along with your food, even if it is before noon.
Mon Ami Gabi at the Paris is a sidewalk bistro with a great view of the Strip. Weekend brunch is served until 4 p.m., giving you plenty of time to rest up after an evening out. If the night before was a little too much, you may want a place like Bar + Bistro Hangover Brunch, where great food can help you get past any ills from the previous evening.
You may want to just keep the party going, and if that's the case, LAVO at the Palazzo has a brunch for you. LAVO just transplanted their New York City brunch to their Las Vegas location, adding a touch of nightclub flair to the event.
For old style Vegas, wait until Sunday and visit the Sterling Brunch at Bally's. This brunch has been around for a couple of decades, and its selection of food leans toward the upscale: lobster, filet, and caviar. Wynn Buffet also serves a first-class brunch, and on the weekends adds champagne.
If a buffet sounds just right, you'll find plenty in town. This traditional Las Vegas brunch spot can be found at almost every hotel, although some brunch favorites include Le Village and Green Valley Ranch's Feast Buffet.