Meetup.com find a group in your area that you are interested in then you have the ice breaker sorted because you are there for the same thing. If you like the vibe go again, if not find a new group.
I've witnessed a meetup from a distance and it looks like a truly awful experience. Just 20 adults cacaphonously making small talk with one another in a huge group. I can't stand large social gatherings.
I use to be afraid of large groups until I realized its easier to get away from someone at a party than it is in a small gathering or one on one situation.