Guess who rules the roost? Dan Gheesling, a 25-year-school Catholic school teacher from Michigan, outlasted the competition to win "Big Brother 10" -- and the $500,000 grand prize. What's he going to do with the money? And how surprised is he to be the last houseguest standing? Click to find out!

"You have to out-think 12 other people, and coming into this house I didn't think I could do it," Gheesling admits to ET. "There's so many huge personalities, manipulators. For me to come out on top, I surprised myself."

Most shocking of all to Gheesling was the fact that his competitors-turned-jurors unanimously declared him the winner over fellow finalist Memphis Garrett in a 7-0 vote.

"I was maybe that cockroach that stuck around after a nuclear blast because I'm still here and I won," Gheesling jokes.