The Idiotarod is a shopping cart race in which teams of five or more "idiots" with a (sometimes modified) grocery store shopping cart run through the streets of a major metropolitan area. The carts are usually themed and feature people in costumes. The races are fun competitions where sabotage, costume, and presentation, and other efforts are rewarded; some cities offer a "Best in Show" prize. Sabotage, such as tripping competitors, throwing marbles or large obstacles in their paths, and the spreading of misinformation such as false route information, were common in the early years. A push for "leave no trace" actions has been promoted recently.