The fireworks are part of a show called Universal 360. It is shown every night(throughout the year) at 9:45 pm. Scenes from movies spanning the last few decades are projected on 4 story high globes that are floating throughout the lagoon accompanied by great fireworks, pyrotechnics and other special effects. Even with the major crowds now we were able to get a great spot to view them -anywhere around the lagoon. It is well worth it. My DD and DS loved it so much we stayed to watch the show several times. The show lasts about 15 min.
Have a great trip.