While I waited for the train back to Seoul, I sat in a café and watched the TV. This remarkable game show was playing, which I now know to be the Korean version of the Japanese game show, Brain Wall, Human Tetris, or Tonneruzu no Minasan no Okage deshita (とんねるずのみなさんのおかげでした), or in the UK, Hole in the Wall.
If you're not familiar with it: C-list celebrities stand on the edge of a pool. A moving wall is revealed with one or more holes in it. This sweeps toward the celebrities, and they attempt to stay out of the pool. I thought there might be something more to it, but it turns out that there isn't much more.