Fireworks

Fireworks in Vosca are actually fairly common if you know where to look, the secrets of gunpowder and its use in such displays reached the West centuries ago. 
In Karthack, many of the less talented Zophs more or less make a living producing the things, since the craft requires no magic but carries the same prestige. Setting off fireworks during the Eclipse is a common method of "fighting back" against the Dark Watchers.
In the Genosian world, fireworks are less common, as their sensibilities tend to discourage frivolities--but even so, nothing prevents the nobility of Illegon from setting the things off at all hours of the night to celebrate their weddings and birthdays. There was, very briefly, a movement in the Ruvian Church to celebrate certain Saints' feast days with fireworks, perhaps by designating a certain color or style in their honor. Pontifatrix Lea II quickly silenced this movement on the grounds that it was heresy and would also be absurdly expensive.