Bonsai is a SCM tool that lets you perform queries on the contents of a CVS archive; you can: get a list of checkins, see what checkins have been made by a given person, or on a given CVS branch, or in a particular time period.
Bonsai is a really cool idea on how to "see" changes taking place during a development cycle. The original implementation was by Terry Weissman, first done in Tcl, then later ported to Perl. It's built to run against CVS using Perl, MySQL, and your favorite webserver to display checkin history, log information, diffs, and other assorted pieces of information in easy to parse HTML.
EMJ: I haven't found anything about why it got changed to Perl, or if the Tcl verson is still around anywhere.
PT: Roughly the same thing happened to bugzilla. I think that Netscape have a lot of Perl hackers and no Tcl hackers is probably the main issue.