The Mole was a show in which there were eight contestants, and one of them worked for the network. They would go through challenges while being sabotaged by the titular Mole, whose identity we do not learn until the end. The challenges are both physical and intellectual, and can be really weird, like using clues to find tickets for a carriage in library books and then running to the designated spots to catch the carriage. Or they can be just random things, like herding sheep, or hand-washing a load of laundry. It took place all over Europe, and was hosted by Andersen Cooper. The original season is available on DVD, and only about 8 or 9 episodes long. It's worth a look. I loved that show so much as a kid, and watched it again last year.