It’s sort of a cut-and-paste job, but Vince Veneziani took a non-functional Sega Dreamcast and turned it into a guitar amp. The 1/4-inch jacks come out of the B and C controller ports, and the speaker (must be a small practice amp) is stuck where the fan used to be.
Ah Dreamcast, we will keep you in our hearts forever.
Dreamcast Guitar Amp [Mac]