Become a samurai and slice through your opponents, even if you do not own a Wii. The Katana application lets you pull out the sword, then swing your iPhone/touch at the evil-doers until they are defeated. Sound effects though your headphones or speaker include weapon noises and your enemies’ defeat when you put your sword back in its scabbard. Katana is on sale 30% through February 28. You can get a copy at the App Store for $1.99.