Analog Terminal Bell
One of the comments on the youtube video says "I need an analog carriage return".<p>Now <i>that</i> would be cool.  Having a physical bell ding every time you hit enter, like an old typewriter!<p>Edit: I'm aware that typewriters ding before you get to the end, but that would be much harder to implement than just doing it when you hit enter, which would be a close representation. :P