Bock: Beeradvocate.com says that the origins of bock beer are arguable. The most popular theory is that the name comes from a pagan influence that the beer was only to be brewed during the sign of the Capricorn goat and that "bock" means goat in German. Basically this beer was a symbol of better times to come and moving away from winter. Nowadays, it is a bottom fermenting lager that generally takes extra months of lagering (cold storage) to smooth out such a strong brew. Bock beer in general is stronger than your typical lager, more of a robust malt character with a dark amber to brown hue. Hop bitterness can be assertive enough to balance though must not get in the way of the malt flavor, most are only lightly hopped.
Doppelbock: Double Bocks or Doppelbocks are huge beers with lots and lots of malt. They are full-bodied in flavor and darker than other bocks with a higher level of alcohol also. The range in color from dark amber to nearly black. Dark versions may have slight chocolate or roasted characters.
Maibock: The Maibock style of beer tends to be lighter in color than other Bock beers and often has a significant hop character with a noticeable alcohol around the same as a traditional Bock. Maibocks are customarily served in the spring and are oftentimes interrelated with spring festivals and celebrations more often in the month of May.
German Pilsener: The Pilsner beer was first brewed in Bohemia, a German-speaking province in the old Austrian Empire - now in the Czech Republic. Pilsner is one of the most popular styles of lager beers in Germany, and in many other countries. It’s often spelled as "Pilsener" and often times abbreviated as "Pils." Classic German Pilsners are very light straw to golden in color. Head should be dense and rich. They are also well-hopped, and exhibit a spicy herbal or floral aroma and flavor and distribute a flash of citrus. Hop bitterness can be high.
Oktoberfest or Märzen: Beeradvocate.com says that before refrigeration, it was nearly impossible to brew beer in the summer due to the hot weather and bacterial infections. Brewing ended with the coming of spring, and began again in the fall. Most were brewed in March (Märzen). These brews were kept in cold storage over the spring and summer months, or brewed with a higher alcohol content so they’d keep. Märzenbier is full-bodied, rich, toasty, typically dark copper in color with a medium to high alcohol content.
Note: The common Munich Oktoberfest beer served at the celebration of Oktoberfest contains only 4.5% alcohol by volume, is dark/copper in color, has a mild hop profile and is typically labeled as a Bavarian Märzenbier in style.
Rauchbier: The Rauchbier style is an old world German beer style. "Rauch" is German for "smoke." The malts used have literally been dried over an open beech wood fire imparting unique smokey qualities into the beer. The beer is typically dark in color and has similarities of the Oktoberfestbier. This is definitely an acquired taste. Imagine a smokiness so robust, so assertive that it tastes of spiced, smoked meat.
Schwarzbier: "Shvahrts-beer" is simply German for black beer. It doesn’t mean that it’s necessarily heavy in body though, in fact, Schwarzbier tend to be lighter in body. Unlike other dark beers, like porters or stouts, they are not overly bitter with burnt and roasted malt characteristics that the others tend to depend on. Instead, hops are used for a good portion of the bitterness. Very refreshing beers, they are great in Summer and Winter. Especially when you are looking for a lighter beer, but one with depth of color and taste.