Sesame Place in Langhorne, PA (Philly area) is a great park if you have younger children. This park has hours and hours of fun including rides, shows and a parade. We went back in 2010 so a lot could have changed since then but it's definitely a place to check out.
Downfall: The price. Back in 2010 it was close to $200 for 3 people to get in. Upon looking today, as I post this, the ticket price is $59.99 which will bring you to about the same, so at least the ticket prices didn't increase tremendously over 9 years, but still pricey.