Munich's Oktoberfest contains 34 tents holds a total of 103,527 seats. Even with that many, you still are going to need a reservation if you expect to sit down.
The smallest tent is the Wirtshaus im Schichtl, which hosts one of Oktoberfest's strangest and longest traditions. The tent is part dinner, part theater, and on stage every hour it stages a guillotine beheading, the same as it has done every Oktoberfest day since 1869.
The largest tent is Paulaner's Winzerer Fähndl, with 10,900 seats including the Biergarten outside.
No matter which tent you choose, it will serve only one of Munich's six Biers, and only Munich-brewed Biers are available anywhere inside Oktoberfest. But don't worry; at the Bavarian Bierhaus you can get five of Munich's "Big Six" and several more from across Germany.*
*Löwenbräu, is the only one of Munich's Biers we don't serve. You can't get it anywhere inside the States. It was brewed in the U.S. under license by Miller Brewing company from 1975 through the 1990s. While the label was the same, the beer itself bore little resemblance to the German original and the brand hasn't recovered since.