@Pink_Hat: first one I had was perfect dark on the gameboy color. The cartridge took like a AA battery, pretty sure it made more noise than vibrations.
I forgot about that until just now.

@Doomguy666: Aw hell yea, Gameboy rumble-carts. They actually take a AAA. I have two of those, Pokémon Pinball and Pokémon Pinball but it's the Japanese version. The latter of which can only toggle the rumble on and off while the former can adjust it. They're so friggin cool, if a bit of a pain in the behind to store conveniently, much like the Kirby gyroscope-cart