Widdershins wrote an interesting post reflecting on how inscrutable Japanese culture can often seem to us Americans. He provides a link to an excellent series of articles entitled Tokyo on One Cliché a Day. It reminded me of some of the other interesting Japan sites I've come across.
The Japanese have developed some innovative new ways of using the English language. It's called Engrish.
Clearly sensibilities with regard to flavoring ice cream in Japan are vastly different from in America.
I'm pretty sure that YATTA! is culturally impenetrable to anyone outside of Japan.
One easy way of delving into Japanese culture is by becoming a t-shirt ninja.
Another way of exposing yourself to Japanese culture is to follow the step-by-step instructions in the Universal Guide to Getting Laid in Japan. Doing that will give you a perfect opportunity to visit all the Japanese love hotels.