[rosensan]

Look up events in your area and go to some that sound cool, even if they aren't the sort of thing you would normally do. Find cheap concerts for music you normally don't listen to. It doesn't matter if you go alone - tons of people do, especially for less well known bands. Learn a hobby about making something, even if it's just a better dinner. Or take a class on making things (woodworking, metalworking, pottery, sewing, whatever). Among the people in tech I know, photography and running also seem to be popular. Next thing you know, there won't be enough time after work to do half the things you want to do.

Look for hobby groups at work as well. For a medium to large company, there are probably a lot. We have a casual after work board game club that gets together once a week, for instance.