There's been a lot of talk this year about the Mayan calendar, but I've been working on a Whiskey Calendar that has no doomsday (though, come to think of it, maybe it should have Bloomsday).
It's a solar calendar, rather tightly aligned with the Julian Calendar, whose key dates are November 30 and March 17 -- St. Andrew's Day and St. Patrick's Day, respectively. As you know, St. Andrew's Day is particularly well-suited for drinking Scotch whisky, and St. Patrick's Day for drinking Irish whiskey.
To my mind, that means the days midway between November 30 and March 17 -- January 23 the short way and July 23 the long way -- are particularly well-suited for drinking both whiskies. (And, if possible, for a pub crawl from your neighborhood Scottish pub to your neighborhood Irish pub (in January; in July, you'd go from the Irish to the Scottish, marking the change of seasons).)
On the above whiskey calendar, I've also marked Bourbon Month (or Jack Daniel's birthday, if you prefer; let's not fight over it) and -- my own pet cause -- Hot Scotch and Lemon Day.
There are, of course, plenty of other days customarily observed with drink (each weekend might be counted a movable feast), but not necessarily with whiskey. Christmas and New Year's Eve are the obvious ones, and I've also left off the Fourth of July as more of a beer day.
Still, July 1 might be a good day for a glass of Canadian whisky, and I'm sure Penderyn would be happy to see St. David's Day added. It may even be time to set aside a day, though I couldn't say which, to raise a dram at your neighborhood Japanese pub. (But I'm terribly sorry, English Whisky Co.: if I'm celebrating St. George's Day it's with a pint of real ale.)
So what other dates really do need to be on any respectable whiskey calendar?