Needs more work on the alignment of the balls!
Step 1: Materials
1/8 inch brass welding rod.
A couple of batteries.
You may also want to reference my knife switch instructable. A simple slider will ruin the effect!
Other materials will be presented as the build unfolds...
Step 2: Prepare the marbles
The marbles will also need a small patch of roughed up area for contact. Again I used the Dremel and an abrasive wheel to grind a small flat on the surface.
The flat of the LED is glued to the ground spot on the marble using Cyano type super glue. This glue has the added benefit of filling all of the grind marks and making an optically pure connection. The last pic clearly shows the LED on the other side of the marble.