Interestingly enough when I started cycling a lot I grew my hair - pony tails are just so much less messy looking on me than helmet hair......

Would a fun cap (I'm thinking something like the little round cloth style ones or newsboy type - not baseball) or buff style head wrap be acceptable at work? A head wrap even with somewhat messy hair (in fact spiky gelled hair could be even better) sticking up out of the top could be cute.