"N.E.R.D.S. (National Espionage, Rescue, and Defense Society)" by Michael Buckley (Book 1)

What happens when the football star goes from being B.M.O.C. (Big Man on Campus) to a nerd overnight thanks to a new set of braces? He joins a team of fellow unpopular fifth-graders with some pretty amazing abilities to form N.E.R.D.S., the National Espionage, Rescue, and Defense Society. Can this team of misfits save the world from their secret headquarters in the basement of their elementary school? Can you read N.E.R.D.S. without laughing? Go ahead and try!