I've written a little script to go through contrib and generate a markdown page showing what the last update time for the files it finds, all the way back to the start of the year. At some point I may extend it to go into previous years as well, but except for during early January of each year the current system should be sufficient to keep an eye on what's new/updated on contrib.
I've set up a cron job to update the page daily: http://csplan9.rit.edu/users/john/contrib.html John -- "Object-oriented design is the roman numerals of computing" -- Rob Pike