Have a trash can shoot-out competition.
Set up a court with a trash basket and tape "free throw line". Using balled-up paper take 5 shots and see who's the office hot shot. Make it interesting with a prize for the winner: a gift card for lunch or coffee, a get off work 30 minutes early" card or other small gift.
Create your own bracket competition.
If you're in a sales environment, create teams and make a sales bracket contest. Award the winning team with a prize... and a trophy. Make it an annual event and pass the trophy on to each year's winner.