Jack-O-Lanterns or pumpkin/turnip carving is an Irish tradition that has been passed on for many generations forming into what we see today, with high variation in style and usage.
Read more about Jack O'Lantern history at this site
Jack-O-Lanterns are the original biodegradable Halloween item. Its one of the reasons I personally love the tradition, and I try a new way to carve & decorate it every year.
Here are the pumpkins we carved in the lab this year.