For the teenage girl: What about headbands? J Crew and the Gap are both showing all sorts of fabric headbands for summer. You could use them for inspiration (maybe duplicate their fabric selections...?)
OR a little totebag purse. Many of the teens around here are toting little summer bags in fun fabrics, with monograms.
I'll try to think about what a boy might like...I have girls and am girly-girl myself, so thinking of boy stuff is hard for me!
