Good news for anyone interested in learning the Japanese or Korean language...
The Japanese and Korean courses for English speakers on Duolingo have been in the incubator for some time now. But as of yesterday, these two courses are available for all users.
I don't know anything about Korean, but I started the Japanese course yesterday and I am already on level 6. Duolingo is specially useful for learning Japanese, because memorizing all those Kanji characters requires a lot of repetition (around 2,000 of them are usually used in Japanese).