There are plenty of fun fireworks games out there to play. If you don't like any of the more conventional fireworks games you can always invent your own. It is only a good idea to invent your own when you are talking about safe and responsible fireworks usage, however.
Phantom Fireworks, for example, has interactive fireworks displays on their website where you can learn how to work with different fireworks combinations. You can view your name interactively in sparklers. Although it really isn't a fireworks game per se, Phantom Fireworks does have their own version of Hangman that you can play through their Interactive Zone.
You can still play traditional fireworks games such as just seeing whose bottle rockets can travel farthest when they are shot off. You can also get a group of children together on the beach. Rope off an area about six feet wide and twenty feet long. Light sparklers and see which child can throw his sparkler the farthest down the sand, or who can run the greatest distance before his sparkler goes out. If you are a fireworks technician who likes to make new creations when it comes to fireworks, maybe you could hold a contest between local fireworks specialists to see who can come up with the prettiest designs.
You can also see who can get their fireworks properly constructed and shot off faster as a game in order to keep yourself occupied. This probably isn't the smartest thing to do however, given the fact that we should be promoting fireworks safety.
There are games such as fireworks battle which are also an online source for entertainment if you are too inexperienced with real fireworks in order to invent something on that front. Remember that you should never put fireworks in your pocket, even if they're not lit, no matter how easy and convenient that may sound at the time to the novice.