The leftovers have been nibbled into extinction, so now it's time to burn those pumpkin-pie calories and shake off your Beaujolais blur! Sometimes the best way to kick-start a healthy habit is to switch up your usual exercise routine. Many of you probably have a membership to a neighborhood gym like Crunch, 24 Hour Fitness, or Equinox, but the treadmills, ellipticals, and packed classes can become stale and unmotivating after a while. So why not try something new and take a kick-ass fitness class or personal training session this holiday season? Here are five of our faves — including one free one!