How indeed. This is supposed to be a written form of unofficial public institutional knowledge that isn't a good fit for the intranet (also, easier to edit).
The DIKU intranet on KUnet has good and up-to-date information. Rather than duplicate it, here's links to frequently useful bits:
Academic Calender for SCIENCE with nice printable overviews.
Phonebook, where you can lookup the names and/or email addresses of an employee or student, based on their name and/or email address.
Lokaledatabasen where you can check room availability.
Online form for ad hoc booking - if you send an email, you'll just get an autoreply telling you to use this form instead.
The lunch menus for the canteens at HCØ and Bio are available here. The menu for the pharma canteen is supposed to be available here, but it doesn't work as of this writing.