Northern Liberties IronWorks

For her Thursday-night ­Cardio Hoop Sculpting class in Northern Liberties’ Ironworks, Jennifer Alvarez has custom-designed hoops with PVC piping (and glittery tape), for a heavy, wide hoop. The result? The joy of hula hooping plus total body toning—and the giggles you get from a workout based solely on wiggling. >>> Northern Liberties Ironworks, 821 North 2nd Street, 215-923-9400, phillyironworks.com.