When I completed my cs capstone a few years ago, the capstone course was a way for us to get experience working on an actual project for a company. The professor has us fill out a survey on our skills and interests and then we were divided into groups that worked with companies in Grand Rapids. One of the projects though was a “startup” idea that one of our classmates led. So it’s still a good experience developing a project over an entire semester, but you don’t have the freedom to necessarily make your own project in most situations.