Our 11 yr old takes piano lessons
@$65/mo. No other organized extra curricular activities for us. We have a neighborhood pool that we use in the summer, and access to tennis courts that we're planning to use more often (starting today). I plan to start the 6 yr old with piano this summer when he's 6.5. The youngest is in preschool and that's all the activity needed. If any of the kids want to learn another instrument, those will be added.
We have a yard and a neighborhood with other children. Our kids need downtime, especially since they're in school all day, so we make it a point not to stress any of us out with a busy schedule. I was never sports inclined, and hate the thought of spending all of childhood at the sports arenas.
Last summer the oldest did a one week chess camp, for $200, and I felt that was overpriced.
It is, however, annoying that so few families are able to socialize because of their insanely over scheduled lives.