(Not my video, just posting to share the awesome 5a)
Song? And is it on iTunes?
Chanes - Lights Off (feat Karen O)
That was awesome!
some really innovative stuff in there, exactly what 5a needs more of, great job. Also what color string is that that shows up so well under blacklight?
Siiiiiick! Amazing stuff! Really enjoy blacklight videos, too (as long as you can still somewhat see the person, too, which you can here!)
Any light-coloured string will work under blacklight. Neon yellow and green tend to work the best. I suppose white would work pretty good, too. 
So good. That first trick was just crazy.