I am working on a SCRUM project management solution: http://scrumptious.io/
Why? Well, in my current company where I am doing my internship, we wanted to use SCRUM, but couldnt find a resource that was light weight, integrated with 3rd party tools like google cal, github, etc, and was cheap at the same time. As a coder, I decided to work on my own solution for this problem. I know that it may not be very monetizable, but in the long run, I can be proud of it as something I built.