The Nekopi website is designed for Japanese elemetary school children and so the site is all in Japanese, but the language used is simple and there are furigana over the Kanji.
You can learn about Japan (and the rest of the world) in Japanese and through various quizzes and games. To start you off here are some links to various pages...
108 Proverbs for example -
石の上にも三年 (for when you are doing something very difficult and want to give up trying - keep trying for just a little bit longer もう少しがんばってみてください！)
Kanji writing practice - these can be printed out
(look for きのうのこたえ and then 
)
)