this is gonna be a short post only...

try out this game to test your jap skills or a hardcore otaku

Typing Mania 4
http://somoe.org/typing/

Typing Mania 5 (lesser songs)
http://www.sightseekerstudio.com/typingmania/contents/odyssey.html

the game is like o2jam kind of music game but its totally different. you select a song from the list and type out the lyrics (for jap songs its in romanji) accordingly as the singer sings, which is, HARD

well i got to koe this through Random Curiosity, those interested can visit this URL
http://randomc.animeblogger.net/2008/09/06/typing-mania-4-the-game-you-wish-you-didnt-start-playing/all-comments/#comments

good luck! =)