Summary

A light up jackolantern with a slot for a CR 2032 3.3v battery (or similar) and plenty of room for a resistor and led.
The lid does not snap on in any manor. Rather it sits atop the Thing like a real jackolantern

Instructions

Print out the pumpkin and the lid
Clean them up a bit
Obtain two small, flat, conductive pieces of metal (like foil)
Solder the end of a wire onto one, and an appropriate resistor to the other
Glue each small piece of metal onto each inner wall of the battery slot (as to contact each side of the battery)
Attach the wire and resistor to the led
Conceal the resistor behind the battery slot, and glue the led to the floor of the pumpkin in front of the battery slot.
Put the battery in! To turn it off, put the battery in backwards!

Note: you may want to use only one piece of metal and simply coil the end of the resistor as the other battery contact

Jack o' lantern