Microsoft has been sued by a group of interactive television patent holders who claim that Microsoft duped them into granting a royalty-free license on the grounds that the company was not planning to release its own DVR system. Only weeks after negotiations took place between the group of patent holders -- operating under the name Intellivision, unrelated to the 80s game console -- and Microsoft, the corporation launched and started advertising for its Ultimate TV DVR product. The negotiations apparently took place way back in 2001, so it's slightly odd that the inventors waited until January of this year to file their claim to revoke the original licensing deal (and gain unspecified damages, naturally). Microsoft hasn't yet responded to the case other than to file a purely procedural motion, so we'll have to wait to see how this one plays out.