The project is so simple and the outcome so beautiful. We know it's last minute with Halloween being Wednesday, but they may be simpler than trying to carve a jack-o-lantern by then.
Plus, even if they're not complete in time for Halloween, they're great decorations for the entire autumn season. We think the glittered surface would look great on acorn squashes and gourds, too. The photo up top is a beautiful example of this project from Flickr. The lower photo is straight from Martha Stewart. (Re-edited from 2006-10-30)