I've been using an older version of this from Knock Knock for quite some time now; it's the only way I stay organized at my desk without resorting to more than one date book.  I keep my class times listed, as well as a brief description of what needs to be done and by when, and it's been a godsend.  Whenever I have a week that isn't very busy I'll usually use correction tape to clear the dates and re-write them--no reason to waste a sheet I've barely used.