When we moved in, we knew we were going to have to stash most of the boxes somewhere while we work on getting them all unpacked. We had house guests from the day we moved in (just for a few days), and we were going to need to get the office up and running, so the exercise room was the easy choice for all of the boxes. To back up a bit further, when we designed the house and decided to add a fourth bedroom, we certainly didn't need it but thought it would be a good addition. For lack of any other use, we decided it would be the "exercise room." We obviously don't need an exercise room, although we do have a decent amount of random exercise implements that will be great to have in one place. Since we've never had a good indoor space for exercising anywhere else we've lived, and since we do a lot of swimming, biking, and running around town, I'm not sure how often we'll actually use it.
We also go to the gym two to three times a week. Today I went to an ab class before our usual spin class, and in the few minutes before class started, I laid on a mat on the ground and stretched. It felt so good. Even if we never use the exercise room for anything else, I really want to spend some time stretching in there regularly. Once we get the boxes cleared out, what I envision for the exercise room is a mostly-empty room with some shelves to hold our exercise gear (assuming it won't fit in the closet, which it might), a table or desk to hold the computer for when we use exercise videos, and two yoga mats on the floor, inviting us to come in.
Makes me want to stretch right now.