Our kids had a great time at the Sandcastle Club at Beach Club. It's not cheap, but it was a nice break from the kids and allowed them to have other kids (and adults) to play with and talk to.
The price is $11.50 per hour per child, with a 2-hr minimum. The last couple of years the Disney packages have included a discount coupon for the Kids' Clubs, but I haven't heard if the 2014 packages do.