My 10 year old got a black ruffled skirt at Kohls-- it's more of a casual fabric, almost t-shirty, with 2 ruffles. SHe'll wear it over leggings, and with a Kelly Green top she got-- casual in front, with a lace insert in the back... wait, I think this is it: http://www.kohls.com/product/prd-1564071/iz-amy-byer-lace-back-ruched-tee-girls.jsp
Her 13 year old sister will either wear a skirt she got at Sears (same fabric, hi/low) over leggings, or just leggings with a similar shirt. Hers is white, also with a lace insert. She asked me to pick up a scarf in either red or green to go with it; I can do that Black Friday.
My son will wear dress pants with a polo I still have to pick up.