More than 3,500 students from 34 high schools from California, Arizona and Nevada will compete Saturday in the Regional Marching Band and Color Guard Tournament of Champions. Hosting the event are the city and the Mater Dei High School Marching Band and Color Guard. Tickets are $8 for daytime and evening performances. The event is from 9 a.m. to 10:30 p.m. at the Santa Ana Bowl at Flower Street and Civic Center Drive. Information: (714) 957-3784.