It's annoying to lose the page for the game you are currently in or about to join, so how about having a page on tf2center which redirects you to your current lobby page if there is one, or to the frontpage if not.
(A better solution would be to reduce the difference between started and unstarted lobbies. There doesn't seem to be any good reason why started lobbies can't be viewed or joined as spectator. But that's probably more work)
