Pardon my ignorance. I'm getting myself a new city/trail commuter bike--the surly cross-check---and thought, hey, I think I'll try a bit of cyclocross while I'm at it, since the LBS guy who is helping me with the bike (props to Proteus in college park, md.) is setting up a 'cross loop in Silver Spring.
Coming from a commuter who wears T-shirts and shorts, the question I have, is--why the spandex togs? With road bikes, I can see the need for aerodynamics, but what advantage do they give in 'cross?