The technology behind Wii Fit is the subject of this latest lawsuit.
http://www.nintendoworldreport.com/news/22903
Maryland based company IA Labs, also known as Powergrid Fitness, has filed a lawsuit against Nintendo, claiming that they have infringed two of IA Labs' patents when creating Wii Fit, Wii Fit Plus and several other peripherals. The company claims to have been "irreparably harmed" by the release of the titles.
The patents behind the lawsuit are "Computer interactive isometric exercise system and method for operatively interconnecting the exercise system to a computer system for use as a peripheral" and "Force measurement system for an isometric exercise device". IA Labs claims to have been in contact with Nintendo since 2007 over the possible overlaps of their patents. In several e-mails it showed that IA Labs wanted to license its technology to Nintendo.
They were also in talks about releasing a new peripheral for the Wii and PC called Sqweeze, a controller created to increase physical activity during gameplay. According to IA Labs' founders Greg Merril and Phil Feldman the technology was used in Kilowatt Sport, the Exer-Station controller, Exer-Station Pro and the PowerSquad Leg Joystick.