I agree with Curupira. I started volunteering for an organization that is involved in something I truly believe in - animal welfare. It took a little work on my part to find the right group, but I did.
The organization is run well. It is a non-profit taking no governmental funds. 95% of the money they raise goes towards the care of the animals. 95% of the "staff" is volunteers. They have a save rate of 97%. There isn't anything they won't do for an animal, as long as it leads to a long term quality life. I believe in what they do.
I have developed many very good relationships with people who I have something in common with, but we talk about many different things. Using Facebook, one of the volunteers developed a page for other volunteer groups who are involved in animal rescue. We all get together once a month to socialize. We also have sports teams through our park district.
Finding this group has been a Godsend.