The case was brought up before a learned judge who after listening to the passionate presentation by the ACLU representative, promptly banged his gavel and said "Case dismissed!"
The ACLU lawyer stood up and objected to the ruling and said -
"Your honor, how can you dismiss this case? Surely the Christians have Christmas, Easter and many other observances. And the Jews... why in addition to Passover they have Yom Kippur and Hanukkah - and yet my client and all other Atheists have no such holiday!"
The judge leaned back in his chair and simply said "Obviously your client is too confused to know about or for that matter even celebrate the Atheists holiday!"
The ACLU lawyer pompously said "We are aware of no such holiday for Atheists... just when might that be?"
The judge said "Well it comes every year at the same time... April 1st"
"The fool hath said in his heart there is no God." (Psalm 14:1)