The Japanese Language proficiency test, or JLPT, or "日本語能力試験" (nihongo nôryoku shiken) is a sort of TOEIC (this is en English exam for the non-english speakers), but for Japanese language.
There are 4 levels, from level 4 4級　(yon-kyû) to level 1 1級 (ikkyû). The level 4 is the easiest, the level one is the hardest.
What for? Test your Japanese level, and eventually put on a resume.
The JLPT occurs every year, on the first sunday of december. (yes, sunday, Japanese people are freaks.)
For those who learn japanese, by themselves or at school, this is a good way to practice and test you language level so I suggest you to take it, there are some exam center all around the world ^^

So this year, the JLPT takes place on december, 2nd.
And I applied for level one. Complicated "kanji", idiomatic expressions, proverbs and classical vocabulary even Japanese people have never heard of.
Of course, I am absolutely NOT ready, and I feel like I'm gonna die in less than one week.
Wish me good luck ^^'