Possibly my favourite specimen was the roll-playing Aeolian Orchestrelle. The picture on the website really doesn't do justice to the beautiful intricate oak. The instrument had been painted black, so someone had to remove all that black paint... but the real beauty of it was a lovely warm tone colour and quite a few drawstops. I'd encountered a parlor organ or harmonium as a child in Canada but they were generally in poor repair. This one had the addition of a roll, similar to a player piano roll -- but with the additional twist that the foot pumps seemed to control the speed of the roll, and the various stops could be pulled to change the tone. The roll demonstrated had dynamic instructions and even some pauses marked.
The various mechanical instruments put me in mind of a sort of steampunk pre-cursor to MIDI files. That in turn reminded me of this:
The video is of a sort of robot that fits over the manual of a pipe organ and plays it from a midi file, made by Dorkbot Alba.
Searching for that, in turn, turned up the Odd Musical Instruments website. Some of the contraptions on there make the serpent look quite tame!