To the extent that you can, keep the party raging outside. That means games, food, present-opening -- whatever activity fits into the backyard, go for it. Any time spent outside of the house is time spent not smudging windows, stomping across the sofa in dirty sneakers or rifling through underwear drawers. Instead of your rugs and floors, any dropped ice cream or spilled soda will be reabsorbed into the welcoming arms of Mother Earth via your lawn. Best of all, raccoons will be doing most of the cleanup for you! No, we're kidding, don't hire raccoons. It's cute to watch them work, but they're unreliable, and absolutely terrible at getting stains out of anything but fur.