Once upon a time I made some timelapse software for building videos of hackathons (ludumdare, specifically). It got pretty good traction and the quality/quantity of the timelapses in that community went up, which was really great to see. Now it is fairly obsolete (and so ugly!), but over its lifetime it saw about 50,000 downloads and helped build timelapse videos for everything from game dev hackathons to professional car engine builds to medical research.