In early to mid October, head up to Benezette to see the Elk during rutting season - worth it just to hear the bull elks bugle at dusk. The Cook Forest State Park Cabins are a great place to stay near that area, but they need to be booked a year in advance. https://elkcountryvisitorcenter.com/

A weekend in Pittsburgh, where the Warhol Museum and nearby Mattress Factory are great art visits. https://mattress.org/

And there's this list from Weird Pa, because weird is always good: http://www.weirdus.com/states/pennsylvania/index.php