When I was a senior in college my sister called me up (she was a freshman at the time) and asked me what she could do as a workout in her dorm room because she didn't have time to go to the gym. That launched a book idea, that while I am still proud of my accomplishment today, never actually went anywhere. It was a good idea, still is actually, but I never really marketed it and did anything to push it into the open market. You can now find it at Barnes & Noble's website and Amazon, as well as iBooks. Great idea, but little traction and little sales...but still proud.