Last year, my nephew gave us a beautifully made piece of art that he and his mother worked on together. It is so neat, I still have it displayed on our buffet. It was the first time I had ever seen melted crayon art before and I just love the simplicity behind it. And many of the supplies are likely available at the dollar store, making it fairly cost effective. You will need a small canvas and easel, 1-2 packs of crayons, a hot glue gun and a blow dryer.
First, select about 13 coloured crayons and arrange them in the order that you would like to glue them. A rainbow of crayons will result in a beautiful effect. Next, use a hot glue gun to adhere them to the canvas. This should be done by an adult. Once they are glued on, set the canvas on the easel and be sure to protect your workspace with newspaper. Then, using a blow dryer, heat up the crayon tips until they begin to melt. You may need to adjust the heat setting and use the low setting to avoid too much splattering. The melting process can take quite some time so be prepared to work in shifts. This would make for a great 'rainy day' activity.