Be careful of Meet Up rides. Around here, they have the tendancy to be poorly organized and unsafe. We had a few of our club rides posted on Meet Up a couple of years ago and it was a nightmare. People with broken bikes and no group riding skills.
Ask around at LBS's for local rides, women's rides, etc. Or get on line and do a search for local bike clubs and their schedules of rides. Just be careful of what kind of ride you go to... some bike clubs are very racing oriented, others are more social. Some say "no drop," but don't really mean it.