The basic premise is that a Taskmaster (Greg Davies) and his assistant (Alex Horne--who is the actual Taskmaster) have five comedians perform different bizarre tasks and clips of their attempts are shown to the entire group (and an audience) later. They have no real idea of how well they did compared to the others until the clips are shown on screen (with the exception of the final task which they perform live in front of the audience). The Taskmaster then awards points based on their performances, but can sometimes be quite subjective (often hilariously so).
The show started in 2015 but often has more than one season in a year, so it currently has 15 seasons available. The seasons also vary in length for the first five seasons (between 5 and 8 episodes) before normalizing to their now ten episode format. I was shown sporadic favorite episodes while in Michigan, but have now started at the beginning and have not been disappointed.