The comany selling Grand Theft Auto is recovering from the embarrassment of finding that a programmer sneaked genuine porn onto the GTA DVDs. Game companies routinely try to check every Easter Egg the programmers slip in, but they don't catch them all, and this is one of the worst slip-ups. (In the original Donkey Kong arcade game, if, at the very last moment, having brought your hero to the top of the screen where you could step left to meet the heroine, you instead stepped to the right, she promptly took off her clothes. But there was not much detail to see in those good old days.)
The GTA porn was exposed by a "mod". Computer games get a lot of their sales from people who enjoy making mods or playing them, and in many cases companies will release the tools for modifying games right along with the game disks. People are wondering if game companies will react to this mess by making mods impossible, but that would be like shooting the messenger when you didn't like his message.
I don't think we've seen the last porn surreptitiously delivered with a game. I'd like to suggest the term "XXXster Egg" to refer to this sort of unwelcome surprise.