Traditional drum and bugle corps served as military signaling units and were descended from the early drum and fife corps of the American Revolutionary War. The modern (non-military) equivalent was spearheaded by nonprofit global youth organization, Drum Corps International. Founded in 1972, DCI is currently recognized as the world leader in producing and sanctioning competitive marching music and related stadium events for high school and college students ages 22 and younger. The members of these junior drum and bugle corps — made up of brass, percussion and color guard — spend much of their free time practicing, the result being a thrilling summertime series of visually and aurally appealing musical programs performed on football fields across the country. The best of the best compete in the 2007 Drum Corps International (DCI) World Championship Quarterfinals, which are broadcast live via satellite, in high definition and with 5.1 audio, during a special one-night event tonight in Tampa. Marching is not required. Thurs., Aug. 9, 7 p.m., Regal Citrus Park Stadium 20, 7999 Citrus Park Town Center Mall, Tampa, $18 adults/$15 students, 813-920-9471, fathomevents.com.