From the "truth is stranger than fiction" department: the operators of the website "ThinkGeek.com" were recently served with a cease and desist letter from a law firm representing the National Pork Board, alleging that ThinkGeek was infringing on the trademark "The Other White Meat." The offending product? "Canned Unicorn Meat."
This "product" was listed on ThinkGeek's website on, you guessed it, April Fool's day. The product never existed, nor did ThinkGeek sell (or try to sell) any actual physical item that supposedly contained unicorn meat. It was clearly intended as a joke. However, that didn't stop the National Pork Board from hiring a law firm to send the 12-page long cease and desist letter.
To be sure, it's important for companies to actively monitor their trademarks as a matter of policy. This includes regularly and actively watching / conducting searches for other instances where the mark is being used. Trademark rights can be diluted or lost if the mark owner does not prevent third parties from using (infringing upon) the owner's marks. But it's also important for the owner of a famous mark to understand when a mark is being used for commercial gain, versus when the use would fall under "fair use," which is protected by law. Ordinarily, parody is protected as fair use.
To their credit, the people at ThinkGeek took the letter in good humor, issuing an apology an offering a discount on product purchases to anyone offended by the joke. As for me, I was a little disappointed to learn that the product doesn't exist — I could use more "sparkles" in my diet.