The job I just started (and really love) was a total networking fluke...
I happened to be at the velodrome one night and one of my teammates was volunteering there. It was pretty late by the time everything was taken down so my husband and I offered her a ride home (otherwise she would have had to bus/bike and it was around 10:30pm already) On the way I, jokingly mentioned that I was thinking about getting back into the job market soon. Now I have an unusual job - I'm a medical photographer, so its not like jobs are particularly abundant. But hey, she worked at a hospital, never mind that it was as a commuter coordinator. Amazingly she said she might know of something. She emailed me a contact and I sent off some emails.
Low and behold here I am a few months later, working at a great job. And yup the position was never posted. It was definitely a case of being in the right place at the right time.