The Bucks will give away the ball that was used in the team's 108-95 win that put an end to the Warriors' 24-game win streak.
"There was a lot of excitement around this game and coach [Jason] Kidd said one of the reasons why we pulled off the upset was the environment and our home crowd," Bucks vice president of marketing Dustin Godsey said. "We wanted to find a way to give back to fans."
In order to win the ball, a fan must submit his or her name, email, birth date and ZIP code by Wednesday. In order to win the ball, a fan has to be a resident of Wisconsin who is at least 18 years old.
The winner will be notified by next week.
The ball comes as is and does not include any special markings or autographs.
Ken Goldin of Goldin Auctions told ESPN.com that due to the timeliness of the event, he could see the ball selling for up to $10,000 if sold by the winner in the near future.