Master chip musician Gijs Gieskes has outdone himself this time: his second Walkman tape sequencer controls the Game Boy music cartridge LSDJ via various knobs and circuitry. In other words, the sequencer he built controls both a Walkman tape deck and a Game Boy. Check out this audio sample or this one to hear what all this sounds like. The effect is quite brilliant: a madcap tape deck scratch system with Game Boy music. Forget records and turntables. Tape is the future, man. Link.
The Walkman Sequencer: Tape + Homebrew Sequencer + Nintendo Game Boy