Yesterday, 5/5/5, "cinco de mayo" around here, was also fifth of twelve ( three x 4 ) "century days". What's a "century day"? One of those day's whose digits are all the same. Note, that in the (rest of the) civilized world, the day is noted in decreasing signficance. This year, for example the Fourth of July is 7/4/5 in the USofA. In Europe, it's noted 4/7/5. Today is 5/6/5 in the USofA, 6/5/5 in the rest of the world.
Yesterday, 5/5/5 is identical in all systems. Ambiguity is marginalized. Let's call it "tres cincos". The next one will be 6/6/6, or "tres sies"! For Mr and Mrs Martini III, this will be number 36 in the aniversary dept. That's _three_ x 12, for those of you counting. Or, to put it in terms of threes: its "three to the third plus three times three"
It's three martini time!