Check out the website of the National Park Service  and you’ll be amazed at the sheer number of National Historic Parks, Trails and Monuments under the watchful eye of the U.S. Department of the Interior. They have a handy park search page  where you can enter your ZIP code and find all the parks nearby. For example, I found that twenty four miles away from me is the Potomac Heritage National Scenic Trail, a “National Scenic Trail,” that is absolutely free. Sometimes you have to pay for parking but otherwise the various parks, trails, and such are usually free to the public.
Sticklers out there will say that your taxes pay for the National Historic Parks (they’re right) but visiting a park usually costs no money out of your pocket. So, unless this weekend is dreary like it is around the Baltimore/D.C. area, give the site a look maybe take a little two hour hike this weekend to get the heart pumping and the blood flowing.