We here at Marblehead Patch noticed that #HarryPotter was among the top posts trending today on Twitter. So, in honor of the trend, here are Marblehead Patch's picks for five things linking Marblehead and Harry Potter: 1. We Have a Castle: Castle Rock Park, located off Ocean Avenue on Marblehead Neck, gets its name from the castle-like private home next door. It may not be as large as readers imagine Hogwarts to be, but it offers residents a "magical" view of the Atlantic Ocean. 2. We're Magicians: Local students may not refer to themselves as wizards as they do in the Harry Potter series, …