Careful with the big and unusual words.
I almost hijacked a recent thread with a discussion on Blackadder The Third episode with Samual Johnson's dictionary and words such as contrafibularity, anaspectic, and other such "interesting" words.
In theory it would be rather challenging to have a word of the week, posted on Everything Else and points awarded to posters if they can mange to use that word in Rugby Discussion threads during the week. This would take a keen volunteer administrator to monitor a rather pointless competition, fun as it may be in theory. It is highly unlikely that anyone would stick their hand up to be the administrator of such a competition.