I got around to making a firepit for my witches cauldron this year. I totally ripped the idea off of a couple of tutorials I found on this site. Props to Riverborder, loach160, and jpbailey1for your tutorials.
This one is for under my cauldron, but I will be making a few more. For this I used a bunch of styrofoam skulls I got from kmart after halloween last year for about $1 each, a couple of battery powered lights from amazon, $8 each, an old bin lid, and good stuff with some black paint.
I cut out the center of the skulls, made eyes and a mouth with a drywall saw And then strung lights through the skulls. Other than that I stuck to the tutorials above and it worked well.