I call it the Merry Celeste.
It's a play on the name Mary Celeste, which was a famous ghost ship, and the Celesta (or Celeste), which is a struck-bell keyboard instrument in the orchestra (think of the Dance of the Sugar Plum Fairy).
So what is it?
Amazon sells a set of 25 chromatic handbells (2 octaves worth). I intend to put a solenoid next to each one and drive them with an ATMega.
I'm thinking that the first thing I will do is connect it up to a MIDI shield and play it with a keyboard. I could then use a standard MIDI sequencer to play songs.
Of course, I could also just have the sketch play canned sequences, but that just seems like more work (translating music into custom software).
We'll have to see.
As for the hardware, that ought to be easy. A pair of 74154s can directly drive PNP driver transistors, each sharing four address lines from the controller, and each having an independent enable line. That's 32 outputs - more than enough.
That architecture wouldn't be sufficient for sustaining instruments, because only one solenoid can be addressed at a time, but for this application, that's not an issue.