This technique can be used on any pie that requires two crusts.
Use a star-shaped cookie cutter and treat the cut-out and remaining scraps of crust as if it is cookie dough. Create a good collection of stars (or hearts, or whatever shape you desire to "spangle" your pie). Then paint the portion already on your pie with one egg white. Add one more egg white to your bowl of egg whites and then add a drop of food coloring and mix. Paint your crust with the colored "paint" you've just made.
The first egg white painted on the crust that is not cut-outs will now act like a glue to the cut-outs, decoratively place them on your pie-crust "borders", place foil around the edges and bake as usual.
I'm really sorry, but the pie got eaten before I managed to get a picture of the completed process. I don't have a picture of the one with just the stars, however, you can also cut out strips of crust and paint half of them red using the same method as the blue described for the stars. Here is our "flag version".
Make sure to let your child help in the process of making this pie. Baking with you offers up lots of learning opportunities for children. Let him or her roll dough, use the cookie cutter, paint the stars (use red if you are doing blueberry filling), and measure out ingredients. While you bake talk about our flag and what stars, red, white and blue represent to a United States Citizen. For more information on the symbolism in our flag, check out my blarticle, Flag Day.