ClassDojo WORKS with high schoolers. I use it for class management as an ongoing competition between my 6 classes, part of my student-of-the-month calculation, a fun way to randomly select students, and a cool classroom timer. http://pinterest.com/josephknable/the-dojo-language-arts-fun-is-not-an-oxymoron/
Iaido - This is a "soft" martial art. Basically, Iaido consists of learning "To Draw The Sword". It's harder than it looks and you haven't felt pain until you've been whacked on the arms with a bokken!