A little over a year ago, Apple sued HTC, claiming 20 patent infringements. Recently, we learned that Apple won that case with 2 of those patents. HTC is now suing Apple back using some patents of their own, and also others from companies they've bought recently.
It looks like this patent war will only get worse, but it's probably necessary until the Governments get fed up with all the lawsuits, and start changing the laws that don't really relate to how business is done in the real world, and are enabling many lawsuits over trivial stuff, that shouldn't happen in the first place.
Apple claimed 20 patent infringements, yet the Court could only find 2 of those to be non-trivial. I'm sure Apple tried to find 20 patents of their patents that were as relevant as possible to HTC's phones, and yet the vast majority of them were canceled. On top of that, the patents that eventually won Apple's case are from 1994, and 1996, before the smartphones even existed, let alone the iPhone – so much for patents protecting innovation in the mobile market, when none of the patents in question were even related to the iPhone. This goes to show how broken the patent system really is, when a large percentage of the patents granted, can't hold their own in Court, and yet big companies are still using them to collect license fees or to block competitors out of the market.
Back to HTC, they are claiming infringements on 3 of their patents, and these infringements cover Apple products such as: Macs, iPads, iPhones, iPods, AirPort, Time Capsule and Apple TV. That's basically all Apple's products, and HTC is looking for blood. They are asking Apple to pay them damages as well, and they are asking the Court to give them an injunction over all Apple's products in USA.
We definitely haven't seen the last of these patent battles, and it should get really interesting soon with Google owning Motorola's 17,000 patents. Either they force Microsoft to back off from threatening Android manufacturers, or we'll see some interesting patent battles between them coming soon as well.