One reason I took up photography was to get out of the house. Not the main reason, but a reason. For the last 3 years, I've worked remotely for a company in California, attending to the care and feeding of some of their computer systems. This tends to be a somewhat solitary activity, broken by the occasional phone call or instant message.
For that reason, I attend a lot of photography related events in the area, or just getting together with someone to go out and photograph. Not only do I get some good photos, but I get out to see people.
While I attend the meetings of the local photography clubs, I've found that the internet is a big help in finding these opportunities. From meetup groups on meetup.com to flickr to facebook, I've been able to find people to go out with, events to photograph and friends to make.
I started with Flickr, first by just uploading photos. But then I decided to attend a local photowalk. Now I go on several a year, and they are always enjoyable. When I went to San Jose last month, I looked for opportunities available when I was there, and that led me to meetup.com. Nothing unfortunately was scheduled the weeks I was there, but I did get ideas. When I got home, I noticed a Facebook friend of mine was attending a local group I hadn't heard of that gets together every now and then on Sunday afternoon to photograph. Since it was an open group invite, I tagged along. I met some new people and got back in touch with some other folks I haven't seen in a while.
The local camera clubs have photowalks and workshops I attend and sometimes run. Also I belong to a couple of internet only photogroups, that while international have people get together.
Being out with others is not only a great way to make friends, but it is a great opportunity to learn something as well as get good photographs. If your not actively looking for these sort of invitations, you are missing out on a lot of good times.