Pretty much all of my "side project" stuff falls into this category in a sense (the sense where "success" means something about "making money"). Some of these

Pretty much all of my "side project" stuff falls into this category in a sense (the sense where "success" means something about "making money"). Some of these things I work on with the hope of making money off of them someday, while others I never really had any financial interest in to begin with. But in either case, I really look at the true value of the projects as being the lessons I learn and the knowledge I gain from working on them. In the end, I figure I learn something from everything I work on, so in the sense that learning is the real goal, all of my projects are ultimately a success to some extent. It's only a question of degree.