Homemade stomp box - now what?

A few weeks ago I got the itch to build something so I settled on a stompbox.  I went to my local Radio Shack and $5 later I had the 1/4" plug and the guts from a piezo buzzer that I soldered together.  I put it inside a wooden craft box and it works great as a trigger.  Now I want some ideas about cool things with it.  Tell me some of your own experiences with these (or similar) items and your favorite set-ups for cool sounds.