Are there any possible activities in his school for advanced kids, like a Junior Great Books club or a science club? Some local libraries also offer board game clubs such as chess and Monopoly. These can be fun activities where it is okay to do well, and may give him the chance to meet like-minded peers.
It's especially important to help your son foster male friendships with other bright boys who can let him know that it's okay to be who he is! They will keep each other involved in acceptable recreational/educational activities through the turbulent adolescent years to come. There is also a new book out that you may find interesting: Smart Boys: Talent, Manhood, & the Search for Meaning by Barbara A. Kerr.