I don't think there is all that much wrong with unfinished projects. Like Procrastinator says sometimes you get so burnt out on a project you think your brains about to bubble over like the head on a keg dropped down the Grand Canyon. I have many unfinished projects I started, but felt I was still lacking in the skills and experience to develop them further at their current stage. As I learn more about the software and how to better translate my ideas into gameplay, I can revisit the files with a fresh new perspective, and a bit more know how.
How about a weekly or monthly challenge? We can either do a small game per month, or a capx per week. Someone can choose a topic that contains two of constructs features and perhaps a Noun or character. Like "A Cat on path with a flash"... or whatever. We make example capx's submit them each week, we vote, winner chooses next topic.