I had this blog post from Craftzine bookmarked on my Google reader and it came in handy a couple of weekends ago while Chris was at work. I used our heart-shaped muffin pan to make some fun shapes (plus I don't use it as often). Just peeling the crayons kept the kids busy for a good half-hour!
And here are the results fresh out of the freezer. I think all but one or two of them broke within the first twenty minutes, but they still work. I had used a combination of cheap and brand-name crayons, and I didn't break them up as small as I probably should have so they took a lot longer to melt. In the end they probably broke because I left them in the freezer too long--the kids weren't going to sit around quietly while they cooled so of course I got a little distracted! I'd definitely try this again, and if I could keep them from breaking it would definitely make a great gift.