My dad just inherited an omnichord. I had never heard of one of these things but now that I've played it I think they are one of the coolest things ever! They are the synthetic son of the autoharp. At any rate, you can pretty much jam out anything on them and it sounds at least decent. This is a video of me jamming on it. I think I might put parts of this jam into an actual intrumental composition. I really like parts of it