Geomamma, have you tried running a group yourself? This year I did Destination Imagination for the first time-- I felt it was a real win in getting the kids excited about doing big projects and thinking hard. I hand-picked the team for social and intellectual fit with my kid (you get to do that if you're running the show).
This isn't the only program of its kind, but it's an example. We have found that you have to be willing to throw yourself into these projects and get to know the other kids to find a good fit.
HTH,
DeeDee