In Catan, can you put the robber on the desert?
On page 5 of the "Base Game Rules" downloadable from catan.com/gamerules.html (describing what happens when you roll a 7, or use a knight card):


  (1) You must move the robber immediately to the number token of any
  other terrain hex or to the desert hex.


(Emphasis mine.)  This page was last updated in January 2012, so I would assume it's a pretty current version of the rules almanac!