For me it was joining the Boy Scouts of America.
I mean I have learned everything there. Public Speaking, teaching, first aid, leadership, service, pioneering, knot tying, climbing, repalling. It has truly changed my life. Working with different things in boyscouts even taught me how to make publications like newsletters and guides. It is really awesome. If you are 11-13 (SIMFISH AND OTHERS) I suggest you get off your bum and check it out!
"Any society that would give up a little liberty to gain a little security will deserve neither and lose both."
-Benjamin Franklin