my favorite spot is the banks on UPenns campus, across the way from the ice rink. Empty most of the time, grind-able/slide-able. you can skate the bank like a ledge because its pretty steep, there are progressively bigger ones, and its near some other west/uni city spots. I am also a huge fan of the big baby blue weird wooden thing near 40th and lancaster, if you dont know what im talking about please go out there and peep