I wanted to do a Fireworks Painting Craft with my son before we go to see the real thing and decided to do this one from the Family Fun Magazine (see video for detailed instructions). It is actually a video of how to make it into a shirt, but thought it would be just as fun to do on paper. Two different Mommy & Me groups that I belonged to have done these shirts and have turned out great so I would definitely recommend trying the shirt version. I liked it because it was simple enough to make with my 2 year old and I already had the supplies.
Basically, you make firework stamps using pipe cleaners- 1 for each color.
Here is my son's finished artwork -I did the one at the top of the post as a way of showing my little guy what to do.