Thanks, Mark. That was fun - my kids and I already tried it.
It didn't really work with the generic, drugstore-type soap bubble mixture we had. But then I remembered I had a jug of high-strength soap bubbles I had whipped up a while back. That soap mixtured worked great! Here's the recipe (just ignore the weird looks you get from the drugstore cashier and mix all this up in an old milk jug):
9 cups distilled water
1 cup Non-Ultra Dawn liquid dish detergent
4 oz glycerine
2 oz KY jelly (hydroxyethylcellulose)