i know exactly what one you're talking about: from tv animation slam dunk: yonkyo taiketsu!.
direct link; video contains no audio, just a word being transformed on screen
i used to have a ROM of this on my sd2snes that would boot straight into it, though i think i lost it at some point.
another fun one might be a micheal jackson game on the ds. it's a music game, and if it detects it's been pirated... it plays a vuvuzela over the music.
another good one is in gimmick; not only is it a reference to the infamous earlier game atlantis no nazo, but it was also something different in the prototype: IMPERFECT VERSION.
there's a lot of neat ones. it's hard to pick.
