Originally Posted by You want to go where?

No, but it is not as contained as the Hofbräuhaus, either. I have spent Rosenmontag in Mainz(where Carnival is very big) two times and there were very big crowds in the historic center with many drunken (but friendly) people. It wasn't a horrible experience by any means, but if you were looking for a more peaceful or sober environment, you would be disappointed.

I haven't been in Munich at Oktoberfest time, so I don't know how much of the festivities strays away from the Oktoberfest venue.

edited to add: Rosenmontag is the Monday before Ash Wednesday and the biggest Carnival day in Mainz. This year it is March 7, 2011.