Altenbaumburg
Altenbaumburg is the namesake of the nearby town in the Palatinate and is the largest ruin in the area.  The Raugraf family owned the castle and because of their stature gave the structure an importance beyond its own merit.  When the family died out in 1358.  The first reliable mention of the castle was in 1253, and by the 1300s the Raugraf family was suffering such economic straits as to pawn off part of the property to others.  Gradually the counts of Palatine gained control of most of the property until they held the entire castle by the 1500s.  During the late 1500s protions of the castle were dismantled and used to build the nearby Ebernburg.  What remained was occupied by Spanish and Swedish troops during the Thirty Years War.  In 1666, the castle was conquered and was largely abandoned as a ruin.  The French completed its destruction in 1689.
What makes Altenbaumburg unique is that it has a lot of undergrowth around the castle grounds.  Therefore, little has been done to rebuild the structure, making the parts visible more authentic.  Moreover, the castle was built in a trapezoidal fashion, probably to follow the terrain more effectively.

To the left, this bridge is obviously relatively new, but shows the nature of the dry moat that protected the outer ward from attack.  The bridge was actually built in the late 1800s to span the dry moat.
Above, some of the outer wall has been smoothed on the top so as to present a more ascethic appearance, and to protect people from falling. 

To the upper right is a section within one of ruined structures showing what is left of an arched ceiling.

Below is an authentic piece of molding, while to the right is a passageway that has been reinforced on the roof to prevent collapse.
Left, a nice view of Ebernburg to the north.
The upper castle is the oldest part of the structure, while the lower portion was added on about 100 years later.  The wall to the right is still in excellent condition overall, having been spared destruction by quarryman assigned to demolish parts of the castle to supply stone for Ebernburg.

These photos were taken in 2008.