I saw down below where someone was asking how long we have to invalidate or send in a submission of a patent up to 6 months after it is published. Does that mean that 3rd parties can not go back and invalidate patents from years ago that never should have been awarded? Some of those most egregious lawsuits involved patents that have been published for quite some time now.
As an example back around April a company called World Inc. started suing major video game companies like Blizzard, regarding patents 8,082,501, 7,493,558, 7,945,856 and 7,181,690 "System and Method for Enabling Users to Interact in a Virtual Space".(original filing, November 1995).
Virtual reality systems to the best of my knowledge were being developed and tested before November 1995(see the guys at VRML - April 1995, but started work in 1994) not to mention many games, although while primitive also used various aspects of what they are claiming. See CitySpace (1993, SIGGRAPH 1994), various Text Based (MUDS), Wolfenstein 3D(July 1995), Worlds Away(September 1995)
I mean you could take their claim and argue that they own the rights to things that every MMPORG has done in the last 20 years. Theres also a lot of other games and other pieces of the games that i mentioned that were using 2D. Just because you go from 2D to 3D, I could argue, doesn't mean that it's a clear invention either.