Went there in 2009, freaking blast.
Bought a leiderhosen-print t-shirt in China when there for work a few months earlier, similar to a tuxedo t-shirt. Huge hit, people were
me at the breakfast buffet. Highly recommend. Ask your front desk concierge where to go for dinner that is not a tourist trap, like Hofbrau-Haus. They sent us in a cab to St. Augustiner, freaking awesome place. Huge outdoor space, great roasted chicken and red cabbage, and awesome beer. Place was a blast, people getting after it aggressively, great time.
Saturday took the train and walked to where they put the "pop-up" structures, which are incredible. You'd never believe they were temporary, exceptional with that said. It's an L-shape setup, with the first end of the L amusement rides with the names all in German, pretty cool to walk through. Hang a right, and there's beer tents on each side. Each tent is a different German brewer. Went the last weekend in September, and around 12PM didn't have to wait more than 5 minutes to get a seat in the Paulaner tent, went there and the Spaten tents. So incredible. Seated at a table with other Germans at the Paulaner tent, gave us a hard time for not speaking German but were otherwise OK. It is freaking insane, band plays constantly and people cheers and chug ever like 5 minutes. You just order beers, since it's the house beer only. Beer was awesome, and a great time. We walked around, some German families reserve tables around the center where the benches are situated, this is the "VIP" area, I thought that was so cool.
Outside, they have their equivalent of the Budweiser horses marching around advertising the respective brands, thought that was awesome and took lots of pictures.
Went to the Spaten tent later in the day, and it was drunkenness like I've never seen in my life. Band playing cover songs, and people just going nuts. Saw people easily 2x my age dancing on the tables of the benches, saw a few people fall right off the tables and just laugh it off/get up and keep going. Saw one guy try to straddle two benches and fail miserably to do so, got up and immediately chugged his beer.
Amazing time, life mission set to do it again at some point in my life.