Peace Valley Nature Center in Doylestown, PA is a nature center that is open to the public all year. They host school programs and public programs that teach a variety of topics/lessons about the environment. They have lot's of activities you can join like birdwatching, hiking etc. It's a beautiful place located in the middle of sprawling (and now built up) sub-burbs. The community is very lucky to have such a facility and staff in their own back yard!