›All Japanese All the Time(Language)- A site with a vast amount of articles, mostly relating to immersion and motivation.

›Joshu(Language)- I haven't used this myself, but it looks promising. Use the blue tabs at the top of the page to click through the site and explore!

›Justhungry(Culture)- This site is mostly centered around Japanese food, but with that comes a good look into Japanese culture.

›Kids Web Japan(Culture)- A cute site that explores many topics of Japan.

›Renshuu(Language)- A good place to quiz yourself on a variety of things. There is a pro version, but you can still do quite a bit without that.

New! ›RocketNews24(English)(News/Culture)- This site is the English counterpart to RocketNews24.com which is Japanese. It's good for those moments when you need a learning break, but want to keep up to speed on Japanese happenings.

›Tofugu(Culture)- A fun site filled with articles that motivate and explore the cultural aspects of Japan. It is also linked to Textfugu(Language), which is a virtual textbook of sorts. There is a fee, but you can try the first Season (chapter) for free.