You go to yahoo groups and join different homeschool lists in your area. Some will be good fits and others you will drop. The ones I like are ones that are just a list where you post different activities.
Like I might post: I am buying a block of tickets to a theater performance at a group rate. Anyone who is interested this is the date and time and cost. Send me the money and your spot is reserved.
Someone else might organize a park day. Someone else might organize a field trip to the nature center or history pioneer village or a meet up at the science center (we all had year passes). Another person might post all the things they find out about already going on around town that are free...like library time specifically for homeschoolers, a parks and rec PE program for homeschoolers, etc.
In my (former) group, you went to as many or as few activities as you wanted to. Sometimes people just listed friend requests...I need a science crazy buddy for a 7 year old boy or I need a family of kids and mom who like to ride bikes on the various bike trails we have (that mom needed for one of them to hang with the slower/younger kids and one of them to ride with the bigger kids).
To tell you the truth...between all the homeschool PE programs, cub scouts, religious education (CCD) class, gymnastics class, and then various fun activities I found on the yahoo list...he was socializing tons more than when he was actually in school.
