Unknown Game

Each Challenge pits numerous cast members from past seasons of reality shows against each other, dividing them into two separate teams according to different criteria, such as gender, which show they first appeared on, whether or not they're veterans or rookies on the show, etc. The two teams compete in numerous missions in order to win prizes and advance in the overall game.

A single bachelor dates multiple women over several weeks, narrowing them down to hopefully find his true love.

Aspiring models compete for a chance to break into the business with a panel of judges critiquing their progress throughout the competition.

The Biggest Loser features obese people competing to win a cash prize by losing the highest percentage of weight relative to their initial weight.