Always can use a helping hand or two: Referees, Game Managers, Photographers, Social Media-ers (kids these days and their instasnaptweets.)
Great way to be a part of a cool community. Play for free, get free drinks at the bars, get discounts for buddies too so you look cool to your pals.
Were you a terrific camp counselor and can translate that to adults? Then you're our (wo)man. Probably the only thing where having camp counselor on your resume is a plus. And your friends who took banking internships said you'd never amount to anything from summer camp. Look at you now! Making a few bucks an hour as a big important dodgeball ref! All those color wars were worth it!