During development of Doom 3, id Software fell into a bit of a patent conflict with Creative.  Relevant snippet from <a href="http://en.wikipedia.org/wiki/Doom_3" rel="nofollow">http://en.wikipedia.org/wiki/Doom_3</a>:<p>"A week before the game's release, it became known that an agreement to include EAX audio technology in Doom 3 reached by id Software and Creative Labs was heavily influenced by a software patent owned by the latter company. The patent dealt with a technique for rendering shadows called Carmack's Reverse, which was developed independently by both John Carmack and programmers at Creative Labs. id Software would have placed themselves under legal liability for using the technique in the finished game, so to defuse the issue, id Software agreed to license Creative Labs sound technologies in exchange for indemnification against lawsuits."<p>I remember something about Carmack coming up with a workaround that paid a performance penalty so others licensing their engine could bypass the Creative mess.<p>Creative has also taken quite a bit of heat over the years for sitting on Aureal's IP and stifling innovation in sound technology, but I don't have specific examples to cite.