Cosby threatened Waxy.org with a cease-and-desist letter (PDF) for hosting the House of Cosbys parody.
While this would most likely qualify as a fair use parody, cease-and-desist letters are usually very effective against individuals who can't afford to fight this in court. Andy puts it well:
But because it takes so little effort to threaten a small web-based artist (or the blogger who hosts their work), the Net is constantly targeted regardless of just cause. Justin Roiland, creator of House of Cosbys, was forced to remove the videos because he couldn't risk the possibility of an actual lawsuit. And when Channel 101 decided to take a stand, Cosby's lawyers targeted their ISP instead, forcing the videos offline. (Read Channel 101's excellent response.)
But Andy is fighting it.
But I know my legal standing, and I'm not backing down unless ordered by the court. This is free speech and creative freedom, and even though it's just one guy's goofy labor of love, that's worth fighting for, dammit.
This was covered in a NY Times article and Kevin provides a few other links too (but sadly no comment).