I take a boot camp/functional fitness training class twice a week. Otherwise, I'm outside.
In the dead of winter, I might take a spin class or go to yoga class. I decide between spin class or my own bike on the trainer at home by the needs of my schedule. I also have a treadmill at home, so no need for the gym there. I'm also outside most of the time in the winter, whether it's snow shoeing, nordic skiing, or running.