Motorcycle Demolition Derby is as crazy as it sounds. Motorcycle riders gather in a circle, and when the green flag is waved try to knock each other down.

"Whoever's standing wins," says David Jackson, assistant event coordinator and announcer for Friday night's Monster Truck Challenge and Thrill Show at the Show Me Center.

Some arenas have banned Motorcycle Demolition Derby. Jackson says he can't speak for their reasons. "We don't have blood and bones," he said, but he recalled a rider having to be removed by ambulance just a few nights earlier. The driver's rear wheel ran over his own foot.

Monster truck and quad races also were on the bill Friday night. The show will be repeated tonight beginning at 7:30.

Some of the riders in the demolition derby are professionals with the touring show, while others are from around the region. "It's like any motor sport -- a good rush," says Randy Lewis, who is one of the touring riders and is in charge of prepping the motorcycles for the show.

The 250cc motorcycles all get a dose of spray paint to hide the bumps and scratches, and there will be some. Some motor sports events are staged on a dirt surface. This show is taking place on the Show Me Center's concrete floor.

Lewis and the other riders wear plenty of padding.

"It's a lot like football," the Cleveland, Ohio, resident said.

By comparison, driving a monster truck like the Devastator sounds safe, but it's not.

Mark Schroeder has found himself and the 10,600-pound Devastator rolling over on an arena floor with the 468-cubic-inch engine belching fire and sometimes exploding.

A typical "gearhead" teen-ager, Schroeder raced drag boats until he went to a monster truck competition. "I thought it was the dumbest thing I had ever seen. But I found out there is a lot more to it," he said.

"It's a good sport, the people that come are really great, and there's money to be made."

How it feels to drive a monster truck is difficult to describe, Schroder says. "To be able to drive over cars is a surreal feeling. It's something we all wish we could do during rush hour."

He built his bright red GMC truck from the ground up. The job took three years and scrimping. "We ate lots of peanut-butter and jelly sandwiches," he said.

Schroeder and his wife, Monique, live near Milwaukee. They have a cleaning business but run their truck every weekend from January through March, the busy season for monster trucks. Racing trucks around the U.S. helps the frigid winter months in Milwaukee go by faster.

They haul their $100,000 truck behind a Peterbilt semi that also serves as their home away from home.

Schroeder beat two of the famous Big Foot trucks last weekend in South Dakota. He is currently sixth in the point standings. To play this game you have to be able to drive and be a mechanic, he says.

To race on the Show Me Center concrete floor, the drivers actually have to reduce their horse power. Otherwise their wheels would just spin.

A monster truck also has to look good and have a catchy name because this is as much a show as a race. The truck already was built before Monique came up with theirs.

"Mark Schroeder and Devastator rolls off your tongue," she said.