If I recall, someone had suggested taekwondo in response to an earlier post? Martial arts can be a great way to develop self-discipline and also a sense of belonging, without playing the clown.

Direct teaching of social skills can be facilitated, in some cases, with books/resources such as:
- The Unwritten Rules of Friendship (which is geared for parents to read and digest so they may guide their children),
- The Gifted Kids' Survival Guide (which is geared for kids but parents may wish to read it first to prepare for meaningful and supportive conversations, following questions their kids may have when they read it),
- Social Thinking (which discusses skills in perspective taking).