My main effort is the Unorthodox-Expert-System. Thirtytwo years of effort so far.
A professor I had in college said that the greatest thing you can do in Computer Science is to make a computer do something subtle that happens in your mind.
A sticking point to this is how do you convince others (or even yourself) that you are doing that, or have succeeded in doing it? I suppose I am working on that very question.