Those of you who remember the “Great White North” segments on SCTV should also remember the favourite brands of Bob and Doug, which were prominently displayed on the set: Molson Canadian, with the occasional Labatt Blue. Very common and widely-available mass-market brews–the Canadian versions of Bud and Miller, you might say. Definitely not Tuborg, or anything else imported or fancy.
A two-four is, as others have said, a case holding 24 beers. “Six packs of two-four” is a usage I’ve never heard outside the McKenzie Brothers’ song–it’s more common to say, “Six two-fours.” But I guess it makes the rhythm work.
And it’s certainly easier to say after you’ve had a few.