BARGE
The BARGE website explains what BARGE is better than I can.
I attended my first BARGE in 1994.
It was through BARGE that I learned about handheld GPS devices (thanks Patti and Bingo!), which got me into hiking.
When I needed to have a medical procedure done in San Francisco, two BARGErs (thanks Patti and Charles) put me up.
I ran my first mile (on July 22nd, 2009) in anticipation of the BARGE Fun Run. I even wrote email to a running friend of mine and told her that I had just run my first mile and I actually enjoyed it but that I hadn't caught the running bug (hah!).
BARGE members tested multibot, my first poker server and are actively using mb2, the poker server I wrote twenty years later.
I owe these people a lot!