Instructables user Beachley is a mechanical engineering student in college, and gave us permission to publish his instructable for all you curious tinkerers here on TreeHugger.
Now, keep in mind that this is a serious project, with serious safety considerations. We do not recommend you take on this project if you don't know what you're doing, and either way, this is an "at your own risk" project. Don't try to win a Darwin Award.
From Beachley: "With Halloween right around the corner, there's no better time to build your very own Tesla Coil! Over the past Summer, I built two Tesla Coils. The first one didn't work, so I started building a second one. This instructable will outline the steps I took."