Though the weather forecast calls for calm, mild weather, it's going to be all about speed, cheers and crashes as locals and professionals race through sand and grass and over pavement at the third annual Boulder Cup cyclocross races this weekend.

Held at the Boulder Reservoir and Harlow Platts Park â behind Fairview High School â the two-day event promotes cyclocross racing, a combination of mountain biking, road racing and mayhem.

Originally beginning in the 1940s as a way for cyclists in Belgium, France and Holland to have fun and stay fit in the winter, cyclocross has gained international recognition and is an official cycling sport, said promotions director Brook Watts.

"In portions of Belgium â the Flanders region, where cycling is a passion â cyclocross is more popular than soccer," Watts said.

The sport even has its own international governing body, the Union Cycliste Internationale, which categorizes races and organizes World Cup cyclocross events.

Sunday's event at Harlow Platts Park will have the highest qualification possible outside of an international race and will attract not only locals but also the top cyclocross racers in the United States, according to Watts.

"It is the fastest growing segment of bicycle racing in the U.S.," Watts said. "It is outgrowing mountain biking, road racing and triathlons."

Incorporating a short, intense track with a variety of terrain and man-made obstacles such as logs and wooden boards, cyclocross consists of athletes cycling, running and carrying their bikes through the course.

The races are broken up into categories including juniors, men, women and elite men and women. In addition, the event will attempt to host the world's largest cruiser bike lap on a cyclocross course.

Race organizer Chris Grealish said that unlike road or mountain bike racing, where the spectator sees the racers ride by every 30 to 40 minutes, the event will have a circus atmosphere where spectators can see at least 80 percent of the action â a pain festival of entertainment, pileups and competition.

"Cyclocross â particularly with the Harlow Platts Park course â is great because you can stand on the hillside and see a tremendous amount of action in one spot," Grealish said. "This is the most easy type of bike racing to watch, film and televise. We think this is the future of cycling."

Grealish said that for the past two years, more than 3,000 fans have come out to watch all of the competitors, especially the elite men and women.

Besides the races, the event will have food available for sale, an expo and a beer garden provided by Boulder Beer, with all the proceeds going to benefit Community Cycles.

"It is going to be an amazing day and a great way to spend an afternoon in town," Grealish said.

Katie Compton, elite women's winner of last year's Boulder Cup, said she's going to come out and enjoy the festivities even though she is nursing an injured leg.

"I am coming up on Sunday to watch and support the other riders, drink some beer and have some fun," said Compton, the current U.S. national champion for cyclocross.

Compton said that although she wishes she was racing, one of the best parts about the Boulder Cup is the crowd.

"There is a great cheering section," Compton said. "Last year, I could barely hear myself breathing."