Get Married on National Ice Cream Day: December 13 2014. 12/13/14.

Maybe it's lucky to get married on Ice Cream Day this year because it's on  12/13/14.  Or if your prefer:  12-13-14.   Or some might see it as 12.13.14.  And finally you could go with 12_13_14.  As far as I know the European calendar would not agree with any of those categorizations of that date.