I have been saving this picture of a wall that plays music until I could find video of it in action:
If you click here they say they have that video, but honestly I could not hear anything. There are some good additional photos of the wall, though.
Also, I was looking for an app that I heard of somewhere that would let me edit the "Keep Calm and Carry On" poster that is everwhere. I didn't find the app, but I found what I had hoped to create already available...so enjoy: