One of my favorite indoor Winter workouts is spinning. While nothing beats biking on the open road, spinning for an hour burns a ton of calories, with the extra bonus of getting to rock out in the saddle. Similar to running on a treadmill, spin class is a perfect opportunity to focus on your cycling technique. Since you don't have to watch out for oncoming traffic or steer around obstacles in the road, you can hone your pedaling technique. Yes, I know the expression, "It is just like riding a bike." But you can really maximize your cycling power by working your legs through the entire revolution of the pedal, not just pushing the pedal down. Plus this will work all the parts of your legs not just your quads, which means you are balancing the strength of your legs.
To learn a simple exercise to experiment with this idea read more.
Keep both feet on your pedals, but work one leg at a time while keeping your other foot clipped in to the pedal or in the foot cage/basket. Focus on making a smooth circle with your pedaling foot to keep the momentum going through the entire revolution of the pedal. Feel your hamstring pull your foot backwards, keep working the back of your leg while you engage your hip flexors to pull the pedal up. You might find, after doing this exercise that one of your legs has a difficult time pedaling solo. This would be your weaker leg and chances are high it has just being going along for the ride.
I try to do this single foot pedal technique for at least a minute per foot every time I am on a spin bike. It helps me balance out my legs and my stroke. Try it and see how it feels.