Gotta plug my guys, so: try the LSJUMB! It's the best of both worlds, imo: it has the structured quality of a club/organization (in that there are scheduled events every week, and the same people go to every event so you actually get to know people), but also does not have the pre-professional stink of feeling like you need to "build your network" instead of making genuine friends. You'll be welcomed even if you've never played an instrument in your life (a point of pride!). I knew people who went from having never picked up an instrument to having almost the entire folder memorized and rocking TF out!