Take up an activity that is kid and adult friendly.
I love to walk, the kids and I walk to the park (4 miles) at least once a week. Once there, they have no use for me! LOL. So it would be a perfect chance to talk with someone, hang out, sit in the sun or throw a frisbee.
Also, hiking, biking, picnic... things that can be done with kids in tow-but still allow for adult friendly conversation and socialization.