Neowin reports SurfCast is suing Microsoft because the "live tiles" in Windows 8, Windows RT and Windows Phone 7/8 allegedly infringe one of SurfCast's "grid & tile user interface" patents.
The patent (6.724.403 (PDF)) in question was submitted in October 2000 and was granted in April 2004. SurfCast claims Microsoft had knowledge of the patent since at least as early as April 2009, and points out that Microsoft's live tiles patent application even mentions the SurfCast tile patent as possible prior art.
SurfCast claims that Microsoft has both directly and indirectly infringed on its patent and wants Microsoft to "account for and pay to SurfCast all damages caused to SurfCast by reason of Microsoft's patent infringement". On SurfCast's website the company says that they designed the "new concept" and filed for the patent related to "Tiles" in October 2000, with it being issued to them in April 2004. In the complaint SurfCast claims that Microsoft had knowledge of the 403 patent at least as early as April 21, 2009.