TomTom has already tussled with Garmin over alleged patent infringement, but it looks like the company has now drawn some ire from a slightly more unexpected source, with Encyclopaedia Britannica now suing it, along with Magellan and, somewhat curiously, American TV & Appliance (a retailer based in Wisconsin). So far, about the only thing that's known about the lawsuit -- which was filed May 21 in the U.S. District Court for the Western District of Wisconsin -- is that Encyclopaedia Britannica is claiming that the companies infringed on some of its patents for a "computerized map system." Exactly how that applies to these three particular companies and not everyone else, we're not sure, though we're sure we'll be hearing more about it soon enough.