Queen Victoria's birth day, May 24th, is a statutory holiday in Canada and the first long weekend since Easter. It is the traditional weekend during which one opens 'the camp' (cottage), and signifies the start of summer (and Blackfly season) in Canada. The reference to 'two-four' rather than 'twenty-fourth' is a Canadian inside joke refering to the obligatory case(s) of 24 bottles of beer, or 'two-fours' required to celebrate the opening of the camp and to steel one's courage against the blackflies and the mice that will have settled into the camp since it was closed in the fall.
"Did ya go to the Beer Store and get a couple of two-fours for camp? It's May two-four, eh, and there'll be a lineup!"
canadian term for the 24th of may (when spring has started and before exams), an international party day on which each person is assumend to have drunk a two-four. may 24th, 2004 was particulatrly spectacular.