It's a promotional tour to help push the winter lineup of GameCube games (and given the company's sales of the console last quarter, it needs all the help it can get!).
Nintendo of America is smart enough to realize that it needs to aim its marketing at a hipper demographic, but Nintendo of Japan vetoes most ideas. Looks like NOA managed to slip this one through. Biggest problem is: The damn tour's not coming to the Northeast, so I can't get my friends at Nintendo to weasel me some free tickets!