D-Day is one of those incredibly easy dates to remember: 6/6/44. (Plus it's conveniently the same both for Americans, who do this illogical thing of going Month/Day/Year, and Europeans, who go Day/Month/Year, smallest measure to largest.) I always do remember it, not only because it's easy, but because (as I mention every so often) I have this thing for military history.
I choke up over D-Day. I am vehemently opposed to wars of aggression like the US's nasty war in Iraq, but the heroic assault by the Allied Forces on the shores of Nazi-occupied France--that gets me where I live. I honor and admire the sacrifice that happened on those beaches in Normandy 65 years ago today. Particularly since it was barely the beginning of the end: eleven months would pass before Germany's unconditional surrender and V-E Day proclaimed on May 8, 1945.
I always observe D-Day, which isn't to say that I celebrate it; I just, well, watch it. I watch its approach on the calendar; I watch its hours pass; I watch night fall and I note that fact that when I wake up the next day, D-Day is over, even though the invasion of those beaches in Normandy would not be completed, in some cases, for days.