ESSEX JUNCTION The fairgrounds at the Champlain Valley Exposition were humming with the sounds of snowmobiles last weekend, as the third annual Rock Maple Racing series hosted its fourth of 10 rounds for the 2007-08 Central series. The snocross snowmobile races zoomed by excited spectators at speeds up to 60 miles-per-hours. In the Big Air competition, riders soared to heights of at least 30 feet, using extreme jumps to launch themselves over 130 feet before hitting the ground. Many of the riders have participated in the famed Winter X-games. Seeing more than a dozen high-powered snowmobiles flying through the air is something you dont want to miss, said Chuck Minasalli, president of Rock Maple Racing. This is an event that brings more than 1,000 racers, support crews, their families and 7,500-plus spectators to the region for a great sports weekend." This years event also included the second annual Go Big or Go Home Semi-Pro Shootout, presented by the Vermont Army National Guard. Last weekend's event featured Doug Decoigne, C.W. Sirjane, Danny Poirer and rookie sensation Darrin Mees.