Puzzle for September 11, 2008

Today is 9-11, now known for in the US for a terrorist-caused emergency. 911 and emergency mean similar things in today's vocabulary.

There are other dates that this is true of, too, like 10-04, 4-11, and others. What National Days are celebrated on these days? Can you think of others? If you wanted to create a holiday that the date was relevant to, what would you pick?