My idea is to dip and soak darts in a flamable material like paint thinner, then attach a lighter on the end of the gun, and then fireing the dart to then have it be a bright streaking dart in the sky. If any one has any ideas that would make it better just post them up.
I've done it. My friend and I were filming a movie involving nerf guns, and we had a seen with fire in it, so we lit some crappy darts on fire and shot them. The foam melts really fast when covered in lighter fluid, and when they melt, they don't fly well. also, the flames go out in less then 8 feet shot from a diskshot because of the air.
Basically, I've tried it and it sucks.