While I have not seen it on TV recently, when I was an exchange student in Japan I used to love watching this with my host siblings. What happens is one person (sometimes more) are at the end of a long runway. One the other end is a wall with some sort of cut out shape in it that the person must fit their body in so that they do not fall into the pool of water behind them. I would seriously laugh so hard that my sides would hurt while watching this. I would like to think of myself as a little more mature now, but I still giggle every time. Here are some videos for you to enjoy.
There are a whole bunch of these clips on Youtube. The easiest way to search for these clips is “human tetris japan.”