Tra-la-laaa!! The NEW YORK TIMES and USA TODAY bestselling Captain Underpants series is now available in ebook edition, featuring Flip-E-Rama, bonus content, and more! When we last saw our heroes, George and Harold, they had been turned into evil zombie nerds doomed to roam a devastated, postapocalyptic planet for all eternity. But why, might you ask, didn't the amazing Captain Underpants save the boys from this frightening fate? Because Tippy Tinkletrousers and his time-tra