Here you are normally taken to a Churrascaria (BBQ) where you serve yourself from a huge salad-, Sushi- and Sashimi-buffet, and are served various cuts of the world's best meats. Brazilian or imported wines, beer, the famous caipirinha drink will help you get into the mood. There's a huge choice of such restaurants, and I'll propose a few from which to chose in accordance with your budget.
After the banquet it is time to proceed to the "Plataforma"-Samba show, where you'll be given a good idea as to what Rio's carnival is all about. A night to remember!
Since you'd be paying by the hour, you might want to chose an evening out on the town of our own design, where I'd help you with my expert suggestions, of course.