Nation's Dumbest

Twelve celebrities report for their first day of class, tackling a logic challenge, a nostalgic quiz on grade-school subjects, and interactive zoology and geography tests as they work their way towards the high-stakes final exam.

The tests get trickier as the all-star students face a mind-boggling lightbulb game, race to answer questions before a balloon bursts, and team up in a spelling bee as they work toward the high-stakes final exam.

After a deceptive challenge, the class receives its first rankings. Then, the all-star students take on an intense chess-themed trivia game and a school picture day challenge as they work toward the high-stakes final exam.

With only nine contestants remaining, tensions rise and rivalries start to form as the celebrities push themselves to their limits, tackling everything from general knowledge trivia to a game of life-sized human labyrinth.

The dreaded midterms are the last chance for the celebrities to avoid being in the bottom half of the class. But will a mystery guest outshine them all?

We're down to the dumbest half, so Jack pairs them off into Study Buddy teams to give them a boost. But are two brains really better than one?

Bonds are tested as the remaining five celebrities battle science, and each other, with explosive results.