I'm sure even if you're not a fan, you've been aware of the Sodoku craze. Seemingly coming out of nowhere, this puzzle has turned into a world-wide phenomenon. It was invented in the 1970s by an Indianapolis architect named Howard Garns. Eventually it got to Japan where it got the name Sodoku, and where a New Zealand puzzle fan named Wayne Gould spotted it. He wrote a computer program for cranking out Sodoku puzzles and rating their difficulty. Here's the part that's of interest to writers, as reported in Time magazine (May 8, 2006):
"He also had a briliant if counter-intuitive marketing model: give the puzzle away. More than 400 newspapers worldwide run his Pappocom sodoku puzzles free in return for promoting Gould's computer program and books. The results must be lucrative, as sales of the books alone have passed 4 million."
Definitely food for thought for authors trying to find new ways to get their work out there!