This is basically beer mecca. OktoberFest is basically Christmas for beer lovers. Don't miss arm day cos the steins are weighty. People actually wear lederhosen here - it's not just an Oktoberfest stereotype. The walking tours are really cool. Even though it's a tourist fest, the Marienplatz square glockenspiel is really cool. Pretzels are delicious.
It definitely helps to brush up on your German language here. Pay attention to the green man - no crossing without him. You'll struggle if you're on a carb diet - potato salad is king.