Mario's Bastard Children
Nintendo normally keeps a fairly tight reign on its properties. Mario is their face, their symbol; thus they strive to make sure that if he's used in a video game, he's used right. The vast majority of Mario games are developed by Nintendo, with an occassional license to a trusted third party like Square (Mario RPG, Mario Hoops) or Hudson (Mario Party) or Camelot (Mario Golf, Mario Tennis, Mario Jai Alai, Mario Shuffleboard).
Except, that is, for a stretch of about four years in the early '90s, when apparently they just handed him out like candy to random passers-by. From 1991 to 1995, nine Mario titles were released by companies other than Nintendo, one of them being Mario's first appearance on the PC, six of which being edutainment titles. They were all made with kids as the intended audience, meaning the name of this article also serves as a good catch-all title for any of the games seen below.