Mike Veeck runs minor league baseball teams and employs a "fun is good" philosophy where he prioritizes creating an enjoyable experience for fans through promotions and giveaways. This approach has transformed money-losing teams into a thriving $25 million business. The book discusses how injecting fun, creativity, and passion is essential for business success. It provides lessons on maintaining a positive attitude, following your passion, blurring hierarchies between management and employees, embracing failure and change, and putting customers first to keep work enjoyable. The goal is to think like a child to retain creativity as adults and make "every day opening day" through constant evolution.