The idea of zen gameplay has kind of blossomed with-in the last few years, but really you could probably trace the idea back to a game like Tetris. There are some games that just are meant to relax you as you play, because you can turn your brain off and just let your fingers do the work (and amazingly, a large number of these games are puzzle based, so the paradox is quite intriguing).
Zen Training is that type of game, where you turn a tree around to catch the falling gems in their correct colour stone areas. Have a look at the trailer.
The music also helps a lot to relax doesn't it? The game is released this week on January 17th.