I got a Pi and a case and connected it via a USB-to-MIDI cable to my electronic piano, and now I can play and record performances to midi files on the Pi. Really cool. It basically gave my piano a technology update so I don't have to spend hundreds of dollars for one of those newer keyboards with a USB port.

My next mini-project is to build a web app that can run these midi tools and list the performances in a nice UI, so that I can control the piano with a tablet or phone on the wifi network (using something other than an SSH terminal).

I am thinking of getting a couple of other Pi's for webcam use. I had one hooked up to a cam but it kept dying for some reason. Maybe because of the cheap wifi dongle.

It's an amazing little gadget and the sky's the limit on what you can do with it.