Remember Nyko's wireless nunchuk controller for the Wii? Seemed kinda pointless to me. Not Nintendo! Thy don't see it as pointless. They see it as an infringement on their patent designs and trademarks, and as such, are suing Nyko, claiming the company's Kama Nunchuk "wholly appropriates the novel shape, design, overall appearance and even the color and materials used in the Nintendo Nunchuk controller". Nyko's response? "We have not knowingly violated anyone's intellectual property and we're still examining this". I don't know whether "we accidentally violated Nintendo's intellectual property" will hold up in court, guys.
Nintendo Sues Nyko Over Copies of Wii Nunchuk Remote [Bloomberg]