I know a lot of the fans don't really care for this Mario game (possibly due to the fact that it's an RPG), but I thought that it was a nice, different edition to both the Mario and RPG genre.
Fun little adventure where you have to team up with 2 other characters to save some star pieces. Colorful, neat graphics for the SNES, and I'll admit that I was pretty excited when I beat this with my cousin. Check it out.
Look for the curtain in the castle you can walk behind that turns you into "classic" Mario