Today is National Whopper day, $1.69 whoppers all day long, and FYI the Crowfoot BK is open til 2am everyday now IIRC.
EDIT: Apologies to all those who went to a BK and got the bad news, apparently it's a sham and no such deals exist. I got the source from RFD, a very reputable deals forum.
THERE ARE NO WHOPPER DEALS FOR $1.69