Puppets that pretend to play instruments to back up your busking or band. Can be scripted to play along with pre-recorded music, attempt to react automatically to incoming audio, or controlled by MIDI / CV. May even have some automatic / autonomous sound generation abilities (drummer can be a stand-alone drum machine, etc.)
Perhaps they could even have band chatter and stage patter through voice recognition. I don't know yet! This is just a placeholder so that I don't forget the idea while I finish my current project.