I was snooping around the web using search engines and looking for cool science stuff to either show my students, or to have them do as projects.  It was late in the school year, so I was thinking about electricity.
One name kept popping up: Bill Beatty
http://www.eskimo.com/~billb/

I went to his site and found all sorts of good info and links.
One of them was to his Tesla Coil page.  I was amazed.  I had to make one myself.  He had a link called "easiest way" which I followed to someone else's site.  The site gave instructions on how to use little more than a car starter, pop bottles, and wire to make a coil.

It worked!  Not well, only making 4" sparks, but I was elated and hooked.