I like this suggestion a lot. Already I can throw out several ideas. Actually several projects evolve around things I need, but I think I can sort them by the hierarchy of needs. There is one I hope will help me fix my health issues, so that should probably have first priority.
solving a problem you have and have a passion for (hat tip to yangyang)
solving a problem you have and have a passion for and is a problem that lots of other people have too
solving a problem you have and have a passion for and is a problem that lots of other people have too and are willing to pay (attention|$$) to solve.