We've been working out more at Planet Fitness due to our ongoing water heater issues. (Hot showers are nice and others appreciate it when we shower regularly, lol.)
PF has a TRUE brand Stretch apparatus in the specialty room.
http://www.truefitness.com/commercial-fitness/flexibility/true-stretch/Look at the floor: it has two angled sections. I've been using this for basic stretching (waist twists, lunges, spiral stretches, etc.) but the angled flooring makes it ideal for simulating edges. My outside edges have improved since I started using this for balancing exercises: inside/outside spirals, one-foot glides (foot forward, backward, tucked) and check positions.
Next time you're at the gym, see if they have a similar apparatus and use it!