I'm speaking of direct ports here (or direct ports with graphical upgrades and no other fundamental changes). The game can be included in a collection or whatever, so long as the entire original game is included. I'm not speaking of multi-system releases ie. Mortal Kombat II which was released at the same time on several systems. What single game has been re-released the most? Just a bit of trivia I was curious about.

I know Super Mario Bros. is way up there:

SMB - NES
SMB All-Stars - SNES
SMB DX? - Game Boy Color
SMB - GBA
SMB - Famicom Mini
SMB - Animal Crossing

and I'm sure a few more that are slipping my mind. I can't think of any others aside from Pac-Man, but I'm sure everyone else can.