If you just have a few minutes available and want to make sure you spend them gaming in the best possible way - it is hard to beat Tetris 99. Nintendo once made Tetris what it is today with the famous Game Boy version back in 1989, and they really took it to the next level with Tetris 99.
Since the launch, Nintendo has on several occasions offered cool themes based on famous Nintendo franchises for the game that you can win simply by playing. All you need to do is earn 100 points starting March 4 until March 9. If you succeed, you will be awarded a Super Mario 3D World + Bowser's Fury theme, which you can check out in the trailer below: