You nailed it. As an example, recently I got back into music, started playing with a band, and then it hit me - there is an opportunity to make some iPad apps to help when on stage and in the practice studio.

You can spend your life as an engineer always looking for other people's problems to solve, and always running out of motivation. When you have your own problem to solve, out of necessity or convenience, the motivation is there by default.

This is great advice. In many industries, what you take for granted (the usefulness of software) is voodoo. Getting a job in any area will expose you to interesting problems that are begging to be solved. Your skills will be unique and valued. If paying work is in short supply, start with volunteering. At minimum, it will get you out of the house and expose you to a new network of people.