Flares are very good for ambient light. Just camCreate them in the air. Drozdov is right, lots of explosions takes you straight to lag city. Making them non-hurtful is another problem.
Whatever you do, I would suggest some kind of looping script - if you don't know how to make a loop checkout the command goto in the online command ref in the Editors Depot.
To make the loop more interesting you could use the command random to change the positions of the explosions/flares.