http://www.google.com/search?hl=en&q=Stammtische
"Stammtische is the plural of the German word Stammtisch.
      A Stammtisch is a regular table where a regular group of
      people meet to drink & eat."

http://www.google.com/search?hl=en&q=Stammtisch

"Literally speaking, the word Stammtisch is a table in a bar or
restaurant which is reserved for the same guests at the same time every
day or every week. There is usually a sign on the table saying
"Stammtisch". If you don't belong to this table, don't attempt to sit
there! In the most traditional German beer halls there is a large brass
plaque above the table with the word Stammtisch printed on it in bold
lettering."

From: storkus@storkus.com
  

Ok, I know this is probably the stupidest question ever brought up here,
but... What, exactly, is a "Stammtische"?  A *fest, hoe-down, or what?
    

I think it means "reserved table".  (Tische = table.)  We reserve a 
table, sit down at it, eat, drink, and talk about $TOPIC.