Prescott Park Arts Festival offers donation-based entertainment events in Portsmouth's Prescott Park throughout every summer. On Monday, July 22 they're screening The Goonies.
People show up early and place their blankets and chairs to save their spots. You are allowed to bring coolers and other packed food into the venue. There are many restaurants within walking distance, and also a kiosk/restaurant on site: https://www.prescottpark.org/about/our-kitchen
Arriving early also makes parking easier. Parking is generally congested in Portsmouth, and these events make it worse. Working out carpooling through this page ahead of time would be very worthwhile. Suggested parking locations are available in the FAQ, below.
Prescott Park Arts Festival is a great organization, please donate at the gate if you can. For all further details about the event, please check out the FAQ.