Friday Fitness:I’m thinking ahead to what I’ll be doing tomorrow for my workout. Because downtown is still mostly dark, there’s a good chance the Equinox I teach at on Fridays will remain closed. I have a sudden itch to run in the brisk November air but Central Park is closed due to the storm, and running through the crowded streets is unappealing and certainly won’t get me out of bed. I may be left with one option: Insanity DVDs, slowly driving my downstairs neighbors crazy…