In Japan, Nintendo has a practice of releasing more mature titles in black boxes. In America, pretty much the opposite is about to happen.
From now on, a range of Mario's DS games in the US will stand out on the shelf with a bright red case, drawing the eye of the customer towards the fact that, hey, these games are probably better than most of the other ones.
It's an interesting branding strategy on the part of Nintendo, though, because between the black Wii boxes and now this, it opens the door for a whole rainbow of plastic game boxes. Green for Zelda, orange for Metroid...something for Tingle.