Just did a casting in Boston and pretty much every kid came in with these coloured elastic bands on their wrists. After a lengthy explanation one young chap made it all clear... they are trading them with each other at school and it has become a nationwide phenomenon. The bands cost $3 for 12 from Walgreens, CVS etc and come in loads of different styles - girl packs, boy packs, safari, glow in the dark etc. Promptly I went off and spent nigh on $20 on rubber bands for my girls, and they went mental for them. I am even sporting one myself. But it's a bit tight to be honest.