All you need are some little pretzels, some green chocolate wafers (melted) and a sheet of waxed paper. (If you want to get fancy, we also had a little coloured sugar for sprinkling, but you do not need it for this to work)
All you need to do is melt your chocolate, and then let the kids get a little messy as they dip their pretzels in. Then have them place the pretzels onto their sheet of waxed paper to form a regular three-leafed clover, or the elusive four-leafed variety.
We sprinkled some green sugar on top while the chocolate was still soft, then we left our treats to dry for about twenty minutes.
When we came back, they were firm, and we could pick them up off the paper and they'd hold their form. (As you can see in the corner of this picture, I also drizzled some of the shamrocks with white chocolate, but since it was prettier in my head than in real life, I'm not going to bring it up.)