A thing that allows you to see if VCS repositories have conflicts with
upstream.  A few components:

- method(s) to add a repository to the monitor
- method(s) of displaying status:
  * web
  * CLI
- automagic updates of the whole repo

For git:
http://stackoverflow.com/questions/10291192/how-to-detect-conflict-between-two-git-repositories

For hg:
hg incoming --patch --git