Summary

Little Jack'o'Lantern Pumpkins sized to fit 5mm (5.5mm inner hole diameter) and 10mm (10.5mm inner hole diameter) LEDs.

Instructions

Either pick one of the two included STL files to print, or modify the OpenSCAD source file to suit your needs.
For the smaller pumpkin for 5mm LEDs, print a 2x2 array of them so the smaller footprints have time to cool between layers. The 10mm LED pumpkins print fine as singles.
Insert LED.
Apply power.
Ooooh! Shiny!