Machines don’t always have a functional purpose; sometimes they are built just to entertain. The machine in the video below takes that concept to a whole new level. It’s only function is to turn itself back off.
After finding this video, I came across an even more awesomely useless machine made by a German hobbyist named Andreas Fiessler. He adapted a broken printer for his machine, which is about the best use I can think of for a broken printer. The video is pretty amusing:
Just in case that video inspires you to make your own, Andreas offers a great description of how he made it happen on his website.