Summary

I printed a really nice diamond shape (http://www.thingiverse.com/thing:19137, thanks cymon) using "Glow in the dark PLA" and attached a handle to it, which results in an everlasting torch light for my little sons.

Instructions

Print the diamond shape of cymon using Glow in the dark PLA ( http://www.thingiverse.com/thing:19137 )
Print the handle (handle.stl). Currently it fits a small child's hand. If you want to change its dimensions I supplied the openscad file as well (handle.scad - you need the diamondcleaned2.stl from http://www.thingiverse.com/thing:19137 for a perfect fit).
Print the handle stick (handle_stick.stl) and use a rubber band to attach the diamond to the handle. There is a small indent on one side to use the tip of the diamond to hold the stick in its position.

This results in an everlasting torch light.

For the diamond I used the "Joris" setting in Cura, which results in a very nice single (about 40 minutes on my Ultimaker)