Apparently, instead of gathering around a speaker, kids like to share music by sticking each other's earbuds into their ears. Maybe I'm just old, but – yuch. To avoid some sort of ear STD, get your offspring the Belkin Rockstar, a circular six-jack headphone splitter that can be used with any MP3 player, including iPhone.
Rockstar has one hard-wired jack for your player (the lime green cable on the left), leaving five open jacks. You also get a cable with terminated at each end with 3.5mm jacks to hook up a second MP3 player allowing those crazy tweens to cross fade between tracks. Rockstar will be coming to town in March and will run you a scant 20 bucks. Seriously, swapping in-ear buds? Do you know where those ears have been?