Japan has a really wide range of pickles. Of course the ginger which comes with sushi is pretty awesome, and Esch already mentioned the pickled plums, and there are so many crazy variations.
The one most common around my area is mizunasu, a stunt, pear-shaped eggplant which has been buried in rice lees for a day or two. This permeates the skin, ferments the eggplant, but the meat deep inside is still raw, so it has a number of textural and taste changes in a single bite.
One I don't like is called shiokara, which are baby squid which are caught and immediately thrown into salt and sealed up. These... well, Japanese say "ferment," I say "rot" for a while, and the sludgy black stuff is eaten with rice or as a side-dish with any alcohol.
