I run an open source programming group that meets once a month in my area and also self-assembles a few times a year at programming conferences I attend. The idea is that we meet for a few hours on Friday night and the meeting is over when there is at least one patch to a project. It's fun and I've made some friends, but there is nothing as rewarding as taking a first-timer and leading them through the process of build/fix/send-patch. It a trivial process as long as someone is in the room to help you through it.

There are a lot of groups like this around the world. Search for "bug mash", "hackerspace", or "hackergarten" in your area. I highly recommend attending something like this. (And if you're in the Basel or Baden-Württemberg area then come out to my group. I'm grilling American hamburgers for everyone tomorrow night).