Met has the answer and Gate has the reasons.
To expand some:
1. Answers not including a Youtube link will be ignored.
2. ...and appropriate videos aren't nearly as rare as you might expect for such a very... niche... game.
http://www.youtube.com/watch?v=0NoTqlp03Xshttp://www.youtube.com/watch?v=NVHsX8oBKIsetc. Pick a song and "Mario Paint" and you've got decent odds of it showing up. (And met stole the obvious link I'd have included as an example.)
They've apparently even hacked Mario Paint's composer to ignore the memory limitations in the original program. Amusing that MP's audio composer got so much use. It's very much a game that became more than a footnote of VG history thanks to YouTube which allowed people to actually share their creations rather than have them rot at home.
3. The physical method of control of this game is simultaneously "bog-standard" as well as "rare," almost unique.... depending on your frame of reference.
http://en.wikipedia.org/wiki/SNES_MouseMore games supported the SNES Mouse than I expected, but a lot are Japan-only dating sims and the like.
4. Italians are such creative types... Michelangelo... Verdi... Fellini...
An artist, a composer, and a movie director. You could make movies in MP! ...that had like 9 frames of tiny size.
5. And if somebody mentions Italians in relation to video games, it's probably either Ezio or the other guy.
I've been playing New Super Mario Bros. DS recently, so was reminded of a certain mustache-wearing mult-talented polymath. (never owned nor played MP incidentally, but a seemingly decently known product regardless.)