usually, double xp weekend for call of duty start around the afternoon on friday and end around the same time on monday. i say usually, though.
edit: i read it starts sometime on thursday, not friday. here:http://www.thisisxbox.com/360/modern-warfare-3-double-xp-this-weekend/
Hi there, I believe the Double XP weekend starts on a Thursday, this information was provided by one of our readers on Game Reviews, generally Playstation also announce any changes to this on there official Sony Blog and Forum.