Normally, books don't have that much merchandise attached until they make it to the big screen. Of course, you'll have a CafePress account with fan-made t-shirts and tote bags, but oficial merchandise is rarely seen until Hollywood starts groping the book. Not so, apparently, with Twilight.
Twilight Teez runs an online shop, where Twilight themed t-shirts can be purchased. These shirts bear lines from the books (She runs with vampires) or book-related slogans (Edward Cullen Fan Club). I quote Charlie Brown: Good grief!
There's also something called the "Eclipse Prom", for fans of the books to dress up in fancy gear and chat about the books all night. The event will take place several months before the release of Eclipse, and I assume it's prom-themed because Bella's prom figures in the plot of the book. Male fans are advised to go up to girls and introduce themselves as Edward.
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