Old Spice are kings when it comes to viral videos and this hilarious video featuring Terry Crews making music with his muscles is an excellent example. Not only is this video funny, but if you wait until it ends, you can actually play all of the instruments by pressing the keys on your keyboard. You might have to click once on the video for it to recognize your keyboard.
I didn’t know that Vimeo had this kind of functionality available for their videos. Really cool stuff.