If you’re not already in line for the new Harry Potter novel, Harry Potter and the Deathly Hallows (out July 21), then ... you can probably just buy it online. Approximately a jillion copies of the final book in J.K. Rowling’s mind-bogglingly popular fantasy series have been printed in anticipation of rabid demand, but that doesn’t mean that single-minded fans won’t be at local bookstores on the night of the 20th, biding their time until the clock strikes midnight by indulging in Potter trivia games, showing off their totally cool Quidditch brooms and Hogwarts uniforms and listening to the latest tunes from Potter tribute band Harry and the Potters. Join them, if you dare.