Brain Snacks: Tasty Tidbits of Knowledge
John Green and David Levithan even collaborated on the main characters' names. David picked "Will" as the first name for both narrators and John picked "Grayson" as the surname. It was a match made in author heaven. (Source)
David Levithan wrote a spin-off to this story called Hold Me Closer: The Tiny Cooper Story, which is a novelized version of the musical featured in Will Grayson, Will Grayson. Yes, it's true: The world needs more Tiny Cooper. (Source)
Will isn't the only one who loves Neutral Milk Hotel. April Ludgate on Parks and Recreation says they're her favorite band, and Stephen Colbert played the song "Holland, 1945" during the final episode of his show, The Colbert Report.