When I joined the track team in high school I was invited to all sorts of things. Getting involved is key, but.... I was in 11th grade by then and never did the party thing, so I usually said "ok, I'll go," but I never would.
I usually only would go to parties in college if my friends were up my ass about it.
I don't really care for parties. The only parties I actually like are the ones my friends in NYC throw. It's usually because there's a nice mix of people and no one's stuck up.