Wow at some of the people in this thread, of COURSE its relevant. Its a pretty great extra-curricular thing, you'd be stupid not to mention it. Its exactly the kind of thing a PS is for.
Anyway, what about this nerd thing? I hate to refer to my own situation again because I don't like to point out that I am Dutch, but here in the Netherlands we have only one word for both meanings; geek and nerd. And that word is nerd. So. If I were to go to Cambridge I'd be a nerd.