I was surprised to see that Fauna has been near the top of the RubyForge most-active list recently:

Based on a clue from Tom Copeland, I pieced together the formula for project activity. For any given week:

activity =
  log(0.3 * number of file downloads) +
  log(number of repository commits) +
  log(3 * number of bugs filed) +
  log(3 * number of forum messages posted) +
  log(4 * number of ended tasks) +
  log(5 * number of files released) +
  log(5 * number of support requests made) +
  log(10 * number of patches filed)

This is then converted into a percentile of all active projects.

It’s interesting that a project can have significant activity even if no developer is working on it.