What Would Happen If You Shot Off Fireworks In Space?

image credit: Rares Dutu cc
The good news: they'll explode! The bad news: they might not be the prettiest fireworks ever. Launching fireworks in a near-zero-oxygen environment is completely feasible.
The trouble would come after launch, when the bursting charge releases and ignites the colorant pellets. The reaction that imparts a rocket's metals and metal salts with enough energy to change pretty colors requires oxygen. There may be some color in the initial explosion, but it wouldn't be half as spectacular as what you see on the Fourth of July.