Simple command to show activity levels

It would be great if there were a way to get a sense of how actively developed a branch is.

This could be either something like Ohloh's information (e.g. "Decreasing year-over-year activity." / "Large development team" / ...), something simple like Launchpad's code page display (e.g. "24 commits by 2 people in the last month"), or a little ascii art graph of num-commits vs time, e.g.:

  2011-02: ====== (6 commits)
  2011-01: === (3 commits)
  2010-12: === (3 commits)

etc.