Professional wand tease J.K. Rowling is at it again: In an Edinburgh-set interview with Oprah Winfrey that will air today, the author opens the door to a potential trilogy of new Harry Potter books. “I could definitely write an eighth, ninth, tenth,†she told Winfrey. “I’m not going to say I won’t. I don’t think I will … I feel I am done, but you never know.†Who’s crossing their fingers hardest right now: Potter fans, the publishing industry, or the Harry Potter actors who could demand roughly 800 billion dollars (we’re estimating) to make a brand-new set of movies? [People]