The Game Boy Player is a device made by Nintendo for the Nintendo GameCube which enables Game Boy (although Super Game Boy enhancements are ignored), Game Boy Color, or Game Boy Advance cartridges to be played on a television. It connects via the high speed parallel port at the bottom of the GameCube and requires use of a boot disc to access the hardware. Unlike devices such as Datel's Advance Game Port, the Game Boy Player does not use software emulation, but instead uses physical hardware nearly identical to that of a Game Boy Advance.
Source: Wikipedia, "Gameboy Player", available under the CC-BY-SA License.