NO, I was also part of the Caleb class. However, my kids do participate in extra curricular activities. I think they teach such great lessons about winning, losing, working with others, supporting others, and trying your best.
Interestingly enough, my brother (who is a current elder) allows his daughter (a pre-teen) to play soccer. I'm thrilled that he is doing that but have no idea how he hasn't been deleted.
I will say that I've had numerous JWs who know my kids participate approach me with questions and want to allow their kids. Almost to a person, these folks are born-ins who didn't get a chance to participate in things they would enjoy. The advice I've given is to all them to do it, just don't advertise it.
Now with only 1 meeting night a week, it makes it much easier to find an activity that doesn't conflict. Sure beats Family Worship (tm)