No elementary-school lunch recess on a warm sunny afternoon is supposed to turn out like this: About 50 boys, all fourth- and fifth-graders, were outside, some shooting baskets, others playfully roughhousing, at the Julia Ward Howe Academic Plus Elementary School in Fern Rock. But suddenly, seven to eight high-school students stormed into the yard swinging aluminum baseball bats at the children, said school district spokesman Fer-nando Gallard. They hit and injured at least 10 boys, according to a note sent to parents from Howe Principal Doaquin R. Jessup. "We don't understand what happened," Gallard said. "This is one of those...