What dates does it take place?

The opening weekend of Pennsic is the last Saturday in July, and the event runs for 2 weeks. If you decide to attend Pennsic for the full two weeks, there will certainly be plenty for you to do. But if you can only make it for a week or less, you'll want to be there during the second week, as that's when the battles and most other events are scheduled. A listing of the dates of future Pennsics is on-line.