chaos,
Exercise with MS can depend on the persons abilities, some of us can do more than others, some have more disabilities than others.
Exercise can be whatever you are able to do, you don't necessarily need to go to the Y or buy expensive equipment. Going for a walk, riding a bike or exercises that can be done from a chair or bed.
Many of us have worked with Physical Therapists and go from there with what was taught/learned.
Exercise is anything you are able to do that gets you moving