Before you hand your dear old dad a tie tomorrow (or, in my case, a do-it-yourself Manhattan kit), be sure to visit the Calendar Man in http://www.trueachievements.com/Batman-Arkham-City-xbox....htm
as Father's Day is one of the 12 days needed to garner the following achievement:
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 day to visit the Calendar Man is July 4th for American Independence Day.