Goal: light off a bunch of fireworks at once... (not necessarily instantaneously, but surely all of them in less than a minute)
Theory: Fireworks tend to be limited in unit-size and cluster-size based on legislation. However, it's sometimes not difficult to combine easy-to-get fireworks into something that that's more impressive. (in that video, they all go off instantaneously, but the goal here is to get them to be more like a superstring)
Result: Even though the rubber cement was sometimes 5" from the rocket nozzle, the rockets had a tendency to blow out the flame whenever they launched. Clearly some sort of oxidizer would help, and possibly something that burns a little more strongly.
Result: Most went off (though a few fell off, because they were cheap and weren't really sturdy enough to rest their whole weight just on their small fuses). However, it was pretty slow overall... there was too much time in between each bottle rocket launching. it would definitely be best to light the fuse from both ends, to double the rate, but it's still slower than you might want. This could be further improved by setting up multiple lines of cannon fuse, and lighting them ALL from both ends, at the same time, but it would be a lot of work to set everything up.
(my brother is concerned that the black powder will push the firecrackers away before they can be ignited... I doubt it, but if this is a problem, perhaps rather than having a circular pile of powder, we could use a line of blackpoweder [1] [2] [3] [4] [5] eg. so it burns a little slower, and isn't concentrated in one area, but still covers a largish area?)
(tip... despite all the videos above of people lighting it directly... you REALLY don't want to do that if there's very much piled up in one place... instead tape a short piece of visco next to the pile, and light that instead (the visco will shoot around otherwise). Or just run a thin line of black powder off to the side, and light that instead (since it will burn slow enough to get your hand out of the way, and won't throw up much heat). Or just light the end of a paper tube, and use that to light the gunpowder instead.)