SAN BERNARDINO, CA—Lakeview Elementary School second-grader Andrew Armbrister went completely nuts with the cowbell during music class Monday, ferociously banging on the percussive instrument for more than five minutes in an effort to produce the loudest sound humanly possible. "Ah yah yah yah yah yah yah yah yah yah yah yah yah," the 7-year-old Armbrister shouted atonally to augment the performance, drowning out music teacher Brenda Noonan's impassioned appeals for him to stop. Noonan told reporters that in the future, Armbrister would be assigned triangle duty.