I had problems with the LED Leaf http://www.thingiverse.com/thing:13997 from 2ROBOTGUY with the slicing in slic3r so i made another one.
Its just a remake of his Version nothing really new, so give all the credits to him.

-print,
-put a battery (3V lithim cell) and a led to it.
-go to the highest floor of your building (best day is on tuesdays)
-throw it (or shoot it with a rubberband slingshot thing)
-look at it
-be happy