International Come up With a Day Day or (ICUWADD) is that day where you feel "wow my job is retarded" and decide to make up a holiday to miss work. Of course because your job always sucks this makes any day that isnt a real holiday (ICUWADD) and allows you to miss every day of work while still claiming a pay check.
Man: "My job sucks"
Joe: "Thats ok dude, its International Come Up With a Day Day"
Man: "I always forget that everyday is ICUWADD, thanks Joe!"
An question replaced "Hello" or "Hi" as the most popular form of casual greeting.
And the answer is from Chinglish, means "Study hard and make progress every day"