I must admit, I was a bit caught off guard when this news was suggested to us, because (until I did a bit of quick research) I had no idea that August 16th had any kind of importance. Unbeknownst to me, August 16th marks the Feast of Saint Roch and is one of the important days necessary to nab the following achievement in https://www.trueachievements.com/Batman-Arkham-City-xbo....htm
As always, you can
pop this achievement the "Cheater Way" by disconnecting your 360 from LIVE, adjusting the date, and visiting, but where's the fun in that?
The next Calendar Man day is September 3rd (Labor Day in the United States).