A NPE (non-producing entity, see also patent troll) named IP Innovation and Technology Licensing Corp. has filed a plaintif against Red Hat and Novell, both Linux distributors, for infringement of US patent 5'072'412. This patent covers the use of multiple desktops to hold one's windows in a structured way.
Not surprisingly, this plaintiff comes right after Steve Ballmer's announcement that Linux selling corporations will fall victim to patent claims in the future. According to an article on Yahoo, IP Innovation LLC is indeed a Microsoft Spinoff – it is lead by a former member of the Microsoft Digital Restrictions Management team.
We have already seen this strategy of spinning off companies through former employees during the Software Patent campaign, where these companies were used to simulate grassroot lobbying – a strategy commonly known as Astroturfing.