You guys. Since this is the Billfold and all: just use baby powder. Main ingredient in most dry shampoos is talc or corn starch anyway. I've been doing that since high school, and still do it when my fancy dry shampoo is at home (always keep a small thing of baby powder in my bag). Works great! However, this trick mainly works for lighter-hair types. As do most powder dry-shampoos anyway.
Caveat: I've never ridden a fixie, but up here in Seattle they sure do have a bad rap for gettin' folks killed. Also: hills. I would drop dead halfway up.
Well, since you asked, It's "hear hear." http://en.wikipedia.org/wiki/Hear,_hear