Name Your Poison Day sounds like a good pick for a Friday. You head into your neighborhood tavern and the bartender gives you a cheerful wave and says "name your poison."
But today is also Best Friends Day, which works well if he or she is close by and can accompany you to the local. You can even say to your bestie, "Name your poison."
Not enough for you? Today is the anniversary of the massacre at the monastery of Lindisfarne. The monastery was established in about 635 and had been at the center of the Christian evangelization of northeast England. By June 8, 793 it was just the sort of soft, fat target that the Vikings found impossible to resist. The raid at Lindisfarne, 1,219 years ago today, is widely regarded as the beginning of the Viking Age.
It's also World Oceans Day. The Canadians proposed this one in 1992, according to Wikipedia.
And if that's still not enough for you, back in 2000 the German Brain Tumor Association selected June 8 as World Brain Tumor Day.
Surely, there's something in all this from which to pick. You simply have to name your poison.