On the way to the supermarket one Saturday morning, I spotted a toy baby grand piano half-buried in a snowbank, ready for trash pickup. My wife pulled over and we safely buckled it into the back seat.
After bringing it home, I found it was a little wobbly, with things jammed into the mechanism, and horribly, horribly out of tune, but it only took a few weeks to fix all of that.
I still don't have enough coordination to play the piano, so I quickly decided to automate the toy. Starting from the Dingbot schematic, I built a new board with a few more drivers and as an afterthought added a MIDI through port in order to chain the instruments together. To make the keys appear as if an invisible person is playing the instrument, I added solenoids under the hammers to push the key levers, using the original mechanism to strike the bars.