anybody know any Japanese myths?

Play Onimusha on PS2 and you'll how rich a mythology they have.

Yes there are many myths in Japanese culture and several good books you can read to get some more background. Be warned though, not all of them are for younger people and some can be quite graphic. I liked the ones about the bamboo and moon princesses. Check most Barns and Noble stores they should have something.

Here are some fun facts!! :
Kappa are supernatural creatures which live both on land and in water. They are as tall as a four or five year old child. They have a beak-like snout, and fins on their hands and feet. They also have a shell on their back, and a water-filled dish on their head. As long as the dish is full of water, kappa keep their supernatural powers. Kappa are known for dragging people into the water and pulling out their livers through their anuses.

Although kappa harm people sometimes, there are also many tales where they have helped people. They are very curious. They often appear in cartoons because of their lovable images.

Kappa love sumo wrestling and cucumbers. That is why cucumber sushi rolls are called "kappa maki". "Okappa" are bobbed hairstyles because they look like the kappa's hairstyles. Kappa are excellent swimmers. There is a saying "Kappa no kawa nagare (a drowning kappa)" which means, even an expert can make mistakes sometimes.

Rokurokubi

Female monsters with long, flexible necks. They look just like ordinary humans
during the day, but at night, they extend their necks to frighten or spy on people. They sometimes turn their human faces into those of demons.

Yuki-Onna

A snow woman, appears in a white kimono on a stormy night. She causes travelers to become lost and freeze to death. Click here to read the story of "Yuki-Onna" by Lafcadio Hearn (Koizumi Yakumo).

Hitotsume-Kozou

A one-eyed goblin, literally has a large eye in the center of its face. It looks like the shaved head of a priest. It does not play tricks, but just scares people.

Tengu

Tengu is a mythical mountain goblin. Tengu has a red face and extremely long nose, and carries a "hauchiwa (feathered fan)." Part man and part bird, tengu have supernatural powers, though they are mischievous rather than evil.

Tengu are worshipped by "yamabushi (mountain priests)," and they usually wear the costume of "yamabushi" with tall "geta (wooden clogs)." Minamoto Yo$hitsune (a great warrior in 12th century) is famous for being taught martial arts and strategy by a tengu on Mt. Kurama, north of Kyoto.

Tengu also have been known to abduct children. In the Kamakura period (1192-1333), there were many sudden disappearance attributed to kidnappings by tengu.