Martinak Park is a large state park located in Denton, MD. There are actually several playgrounds located within the park. There is a small metal playground located within the campground, a newer playground that has a restroom building, and is connected by a path through the woods to the playground near the pavilion. There is another spot near the Nature Center and boat launch with a jungle gym and slide. It's also just a great place to walk the paths and enjoy the water views. http://dnr2.maryland.gov/publiclands/Pages/eastern/martinak.aspx
Can I Ingress Here?
The Google game Ingress, for Android and iPhone, is a GPS-based "capture the flag" game that interacts with "portals". These portals are real world locations that you have to physically go to, such as historical places, artwork, sculptures, parks and other public places, to interact with them via your device. This "game" is an awesome way to get out and see the world around you. www.ingress.com
Nearby Ingress Portals
There are several portals here, including memorials, educational boards, the campground and playground, so there is a portal nearby for every area of the park.