Castle Rock Entertainment, Inc. v. Carol Publishing Group, Inc.
Seinfeld was one of the most-watched television comedies, with over 108 million viewers by the show's end. Even almost a decade after the final episode, the release of the first three seasons of Seinfeld on DVD sold around 4 million copies, which held the record for most single-season TV show sales until it was surpassed by The Chapelle Show.
Even though Castle Rock won its case, and had all un-sold copies of the Seinfeld Aptitude Test destroyed, it is still available for sale. However, there are plenty of other places to look for Seinfeld trivia. If you're unfamiliar with the show, the SeinFAQ is a classic repository of Seinfeld knowledge.
This case is not the only time something Seinfeld related ended up in court. In Mackenzie v. Miller Brewing Co. an employee, Jerold Mackenzie, was fired for sexual harassment after discussing the details of a particular Seinfeld episode, "The Junior Mint," with a co-worker. He sued and was initially awarded $26 million by a jury, but this was overturned on appeal, and the reversal affirmed by the Wisconsin Supreme Court. Eventually, the plaintiff settled out of court for $625,000.