From Wikipedia: Victoria Day is a Canadian Statutory Holiday celebrated on the Monday on or before May 24 in honour of Queen Victoria’s birthday. In Quebec it is referred to as National Patriotes Day (Journée nationale des patriotes), which commemorates the English-Canadian and French-Canadian Patriotes of the Rebellion of 1837.
…This is the first of the summer long weekends in Canada, and is known colloquially as “May two-four weekend”. The phrase has two meanings, the first, of course, is the fact that it usually falls around May 24, and secondly, those who celebrate will often get together to drink beer (a two-four is a case of 24 bottles of beer.) Note that the holiday may be referred to as “May two-four” even if it falls as early as May 18.