"You mean besides us?" Ferb chuckled a little, somewhat amused at his own joke. But really, the idea excited him. He wondered why which people, why the timing. "Has anyone studied it?" He took a swig of his soda. "There has to be some sort of common denominator behind who arrives when and why." He rifled through one of the desk drawers, pleased when he found a snack bag of Doritos.