George Sullivan, who writes tons of sports books for kids, has one called
Don't Step on the Foul Line: Sports Superstitions [J 796.357 SUL]. In it you'll find superstitious athletes such as baseball's Wade Boggs who had 80 rituals, one of which was eating chicken every day of the season!
It you are interested in learning more about humans and why they're so superstitious, look for Believing in Magic: The Psychology of Superstition by Stuart A. Vyse [133.43 VYS].
Maybe your kids might like to read this novel about superstition in baseball: Two Hot Dogs with Everything by Paul Haven [J HAV].
The Sluggers are a baseball team whose past is filled with hundreds of defeats and near misses. Year after year, they play the kind of baseball that challenges the most faithful of fans. But when it comes to Slugger supporters, there’s a whole other category. Die-hard fans who rely on elaborate superstitions to support their team. Fans like Danny Gurkin.Sounds like a fun summer read, doesn't it?
When Danny and his friends learn that a mansion with ties to the Sluggers’ history is slated to be demolished, they make a desperate pilgrimage to see what can be done to save it. There Danny uncovers a flavor of gum created by the original team owner, a 19th-century bubblegum tycoon. Danny helps himself to a few packs and discovers that chewing the gum gives him the ability to alter the Sluggers’ future. But Danny’s secret comes at a price and before long he’s in hot water with just about anyone who has a stake in the game.