http://en.wikipedia.org/wiki/Bock_beer

I suspect many people's first try of Doppelbock is at a Frühlingsfest, the spring beer festival. I'd recommend Munich's Frühlingsfest over the Oktoberfest every time, much lower tourist presence.

You have to be careful though, good bock doesn't taste as strong as it is so you can be much further gone than you think! I like to imagine the monks getting all fighty after drinking it while fasting through Lent!!!