I have a list of ideas. I carry it around in my pocket (in a PDA). They are big ideas, for difficult projects, with commercial viability, such that, if I were the risk-taking sort, I could quit my job, focus on it, and try to make my fortune. I haven't done any of them. Some of the ideas I had years ago have since been realized by others who had the same ideas and formed companies around them.
Today I had my first new idea in about a year, and it's a great one. I'm really excited about it.
I'm not going to tell you what it is, but ask me later if I've worked on it. I don't want this one to just sit in my pocket.