The top ten all-time opening weekend list had a dramatic addition this weekend "Iron Man 3" knocked "Harry Potter and the Deathly Hallows, Pt. 2" from the 2nd slot with a massive $175 .3 million debut. The rest of 2013 should mean more dramatic changes for the list with "Man of Steel," "The Hunger Games: Caching Fire" and - possibly - "Thor: The Dark World" ready to crash the party.  So, before some current champs find themselves forgotten legends, lets rundown the top ten 3-day weekend openers of all time as of May 5, 2013.