The Hobbit:  An Unexpected Journey, which was actually released in late 2012, was the most pirated film of 2013 with over 8 million downloads, according to TorrentFreak, which compiles data from BitTorrent networks.  Three other geek films hit the top ten, with Iron Man 3 at #4, Star Trek Into Darkness at #6, and World War Z at #10. 

Geek films from the top ten domestic grossers that did not make the list include Hunger Games:  Catching Fire and Man of Steel.  Hunger Games was the #2 grossing film in 2013 (behind Iron Man), and Man of Steel was #4. 

The most pirated films chart reflects both popularity and other factors, such as legal digital availability.