If the room you're working with isn't too large or oddly shaped, you can produce a startling effect by draping multicolored pennant banners, streamers or garlands from the center of the ceiling to each of the room's four corners. Think of it as the big top revisited. It'll create a festive atmosphere in a classroom or conference room without much effort or expense. This is a nice touch in a small room or sparsely furnished space without much potential, too. Make sure you have enough ceiling height to work with, though. You don't want anyone to get tangled up in the decorations on the way to the drinks table.