Propeller Beanies!

http://www.propellerheadhats.com/store/

As a full-fledged fan of Beanie & Cecil, I used to wear one of these. The "official" version was (I think), plastic and the rotor had a pull string that could make it fly off, (where it would promptly lodge itself on the roof, in a tree, etc.). Very cool.
I continue to be a slave to fashion.