Did you know that yesterday was Harry Potter’s birthday? I didn’t either. But leave it to our friends at Warner Bros. to remind us.

The studio is marking the occasion with a big sale on Harry Potter merchandise. They’re marking 30 percent off all Harry Potter wands, clothing, personalized gifts and all the rest – including the new 31-disc, limited edition, numbered Harry Potter Wizard’s Collection, which offers 37 hours of special features. The sale ends Aug. 4.

The massive new collection contains all eight Harry Potter movies on Blu-ray, DVD and UltraViolet Digital Copy. The special features includes all previously released materials and nearly 10 hours of new-to-disc bonus content, and 5 hours of never-before-seen material, including an interview between J.K. Rowling with the screenwriter.

The collection also includes exclusive memorabilia designed for the collection by the graphic designers of the films, along with color concept art prints from the films that are suitable for framing, a full-color map of Hogwarts printed on fabric, a series of black-and-white production design concept sketches and a wearable prop replica of the Horcrux locket.

I’ve posted a clip from Rowling’s interview with Steve Kloves, who wrote all of the movies except for one (Harry Potter and the Order of the Phoenix) below.

Harry Potter Wizard’s Collection (Blu-ray)(Dvd)(Digital Copy) Blu-Ray from Warner Bros.