In science fiction, folding space-time leads to jump drives and other modes of interstellar travel (spin up the FTL Drive, Mr. Gaeta!). But there are other reasons you might want to fold space-time -- like making music.
In this video, mathemusician Vi Hart demonstrates a down-to-earth method of folding space-time. All she needs is paper, a music box, and a basic knowledge of music notation. Got seven minutes to learn a little about space, time, and music? Tune in:
So what else can you do with this concept? In 2009, Hart created a Möbius strip containing a theme from the Harry Potter Septet. Because it's a strip, it can be played indefinitely (as long as the cranker keeps cranking), but each pass through inverts the notation due to mathemagic.
And while we're talking about the relationship between space and time, here's a Minute Physics video exploration of the question how far is a second?