Children and their families, schools and youth groups are invited to show they are "Barn to Be Wild" at the Youth Expo Experience, featuring 4-H exhibits, free hay rides, scavenger hunts and petting zoos, and other fun stuff. The O.C. Fair & Event Center, 88 Fair Drive, Costa Mesa. 10 a.m.-5 p.m. Sat.-Sun. Free. Parking $5. (714) 708-1500. http://www.ocfair.com.