http://www.braustuberl.de/veranstaltungen/...6_100110_0.html
Sadly can't make it myself but if the idea of drinking copious amounts of beer outside with lots of people in traditional dress floats your boat then it's Tegernsee Waldfest this weekend.
Held outside the Braustuberl in Tegernsee a few thousand people would be happy to join you. The BOB from munich runs a couple of times an hour.