In keeping with the occasion (albeit somewhat late - the server lost my
previous posts), here's something for lighting up the Jack O' Lantern.

Most of the components are mounted directly on the negative end of the AA
cell. A stiff wire soldered to the positive nipple is used to stand the
light up inside the pumpkin.

With a teaspoon of water inside the pumpkin to improve conductivity, enough
current will flow when the open end of the 220k resistor touches the surface
to light the amber LED to 30mA. Used 10 hours on Hallowe'en night, an
alkaline cell should last 3-5 seasons.

QS
My LED circuits: http://quantsuff.com