A tractor-trailer clipped a school bus full of students Tuesday, flipping the bus onto its side and sending 32 people — 29 of them children — to a central Texas hospital. Police said a 9-year-old boy was ejected through the escape hatch in the bus roof, and the bus driver was knocked unconscious. The accident occurred about 7:30 a.m. on Farm-to-Market Road 93 on the southeastern outskirts of Temple, about 60 miles northeast of Austin.