http://en.wikipedia.org/wiki/Zangeki_no_Reginleiv
With its black cover design, it is the third game to break the tradition of white keep cases for Wii video games; the first two were New Super Mario Bros. Wii and Metroid Prime Trilogy.
It sounds like one of the few worth-playing Wii titles, and it's exotic enough to make you feel special once you do track it down and play it. And I doubt many people have played it 4-player co-op outside Japan, so you'll feel even more special about that too. More info here: http://culture.vg/forum/topic?f=3&t=3112
I've ordered a copy but my Jap Wii is in France and it could be a long while before I find a way to bring it over. So this one's for the long haul. I am only making the thread to give people the heads-up so that whoever's interested starts placing the appropriate orders. Don't disappoint me people! And use this thread to post updates of your progress to acquire all the necessary items (we'll need WiiMotion Plus too).
P.S. Is it possible to play online on hacked Wiis? I am asking for the benefit of those who don't have or aren't interested in acquiring a Japanese Wii -- though you should be because it's cheap and why not.