The tips about not being overbearing (correcting people, giving them unwanted advice) are well taken, but in many circles - especially the ones you actually want to be in - your natural geekiness will be highly valued.

I swear that, at least in parts of SF and NY (not trying to push geographic stereotypes, these are just the places I have personal experience), geekiness is even cool. If you work too hard hiding it, you will have trouble finding these places.