I just came across the story of Limbo of the Lost, a game that has been in development in some form for 15 years, and that in its current incarnation for the PC appears to be the most awe-inspiring case of plagiarism since Giana Sisters. I mean, check out these screenshots.
On June 12th, the game was pulled from release when multiple sites and forums posted screenshots showing items, environments, menu graphics, characters, even fonts stolen from more than a dozen games as well as several movies. Similar screens revealed the company's theft of graphics goes back even to the original version for the Amiga.
Every developer who's been around for a while knows of studios that do so some bad things, but this... this is impressive.