Several years ago my teen on the autism spectrum participated in a social skills group at an agency for one year. The services at many agencies we have been involved with over the years ends at the age of twelve. Some have expanded to serve through fifteen. It has been difficult to find something suitable for a high functioning autistic teen who does online schooling at home. There is no face to face interaction with peers, only virtual discussions on message boards and in class webinars.
We have utilized Workbooks over the years plus the daily calendar that is now available for teens and adults. We also took part in Kids Enjoy Exercise Now (KEEN) program for a few months. While there were other teens there with disabilties, they were not paired together to socialize or play sports together, but instead matched with an adult or older teen as a mentor. This was not a comfortable situation for my teen with no visible disability that would rather meet peers to form relationships and long lasting friendships.
Another option is winter, spring and summer break camps that are geared for various age groups and interests among the autism spectrum. These include sleep away for one or two weeks and sports related activities. The main drawbacks are cost and location.
There are some agencies that help with after school activities that take your teen out in the community with adult assistance. This is something more suitable for someone with behavior issues.
There has never been an interest in learning a specific sport or musical instrument. This does not leave much to pursue in way of forming peer relationships.
Some resources that might be suitable for your family and adolescent on the autism spectrum:
Tips for Running a Teen/Adult Social Group
Class helps autistic teens refine social skills
How can I be a good friend to someone with Autism
Does your teen need social skills coaching - pdf quiz (topic is not specific to autism)
Social Skills and Friendship Group in Seattle
Helping Build Social Skills and Positive Connections
Social Skills DVD Lesson - youtube clip
Educational Autism Tips for Families 71 page resourceful ebook for families entering the school system with a recent autism diagnosis. Find out what issues take place over the course of a school day and meet these challenges head on.