Harry Potter a cause-and-effect relationship, there is a clear correlation, and it seems that Harry Potter's cultural impact may be stronger than just a fandom bond. Many fan fiction and fan art works about "Harry Potter" have been made. In March 2007, "Harry Potter" was the most commonly searched fan fiction subject on the internet. At the University of Michigan in 2009, StarKid Productions performed an original musical parodying the "Harry Potter" series called "A Very Potter Musical". The musical was awarded "Entertainment Weekly"'s 10 Best Viral Videos of 2009. The sport Quidditch, played by characters in the "Harry Potter" series, was
Harry Potter and the Philosopher's Stone 8.3 million in the US. An illustrated version of "Harry Potter and the Philosopher's Stone" was released on October 6, 2015, with illustrations by Jim Kay. The book carries over 100 illustrations and will be followed by illustrated versions of all seven books from the series by the same artist. In 1999, Rowling sold the film rights of the first four "Harry Potter" books to Warner Bros. for a reported £1 million ($1.65 million in 1999). Rowling demanded that the principal cast be kept strictly British but allowed for the casting of Irish actors such as the late Richard Harris