The Mario series is one of the most famous franchises in history, with the protagonist almost always being a plumber named Mario. Almost all of him is trying to save his beloved from the clutches of a huge and powerful monster - Bowser, but sometimes the plot also tells about other events.
Almost all Mario games are 2D and 3D platformers that require good reactions from the gamer. The levels are filled with a lot of collectibles and secrets, and the game itself can be completed in different ways. But there are also exceptions. A good example is Super Mario RPG, which is a role-playing game in the JRPG genre.