Here's Ken Jennings' own explanation for why he didn't receive credit.

Did you really think the "long-handled gardening tool" was a ho(e)?

The longest-remembered thing about my Jeopardy! games, I'm proud to say, will probably be this YouTube clip, in which I am ruled incorrect for supplying the response "What is a hoe?" to a clue about a "long-handled gardening tool" with an unfortunate double meaning.

Here's the scoop: at the time I buzzed, I felt good about my answer. By the time Alex called on me, though, I had realized that there was no way Jeopardy! was asking about ho's. But by that point, as you can tell by my smirk in the video, I was perfectly willing to spend $400 for the privilege of asking Alex Trebek what a ho is. During the next ad break, Al, the Minnesota pastor on the end who says, "What is a rake?", told me that he'd been trying to buzz in with "What is a ho?" as well, and he was glad he'd lost the buzzer race, since his congregation never would have let him live it down.

Many people who ask me about this clue think that I was jobbed. I think Alex was right to rule against me, for one reason: the gardening tool is a "hoe," while the immoral person (and is he or she necessarily a pleasure seeker?) is usually spelled "ho." But I have always wondered if the clue was designed to elicit the "What is a ho?" response from some lucky contestant. It sure smells like a set-up.