The Printing Office is always a great place to visit. It's amazing how each letter had to be put in place and it's great for the kids to see.
They also have a mill and a little farm. There was some turkeys and chickens today. Plenty of buildings to visit and keep everyone busy for the day.
If you are planning a visit during March Break on they also have a Maple show starting at noon and there is horse carriage rides too for $2 a person. See Black Creek's website for more information