I have met some really nice quilters by volunteering at my LQS. When she has a bus load of shoppers coming she needs help cutting fabric, bagging up purchases, managing the snacks, helping shoppers find whatever they need and to watch out for theft. It's a lot of fun.
I almost forgot. The way I first met some quilters when I was just starting out I went on a bus trip. That's a great way to meet quilters.