As adults (most of the time), we're officially past the point of thinking that science is lame. (We know you watched Breaking Bad, don't even front.) At the Chemical Heritage Foundation in Old City, which is always free to visit, you can page through books, instruments and artifacts, art, and photographs detailing the history of chemistry since the early 21st Century. We promise you’ll find it more interesting than your high school chem classes.
Practice your triple lutz at a skating rink
Granted you need to bring your own skates (rentals are just $3), but the City of Philadelphia offers free skating at each of the five public rinks around town. It won’t be as scenic as what you’ll get at Dilworth Park or Penn’s Landing, but they're good options for getting that practice in before hitting the paid rinks. After all, falling at a free rink > falling when you’ve paid for it.