The ACLU defended the right of a student to protest against the ACLU.

Not surprisingly, as ACLU stands for American Civil Liberties Union. In 2009, the ACLU of Virginia wrote the school officials of Gate City High School telling them that the sectarian prayer delivered over the public address system at each football game was constitutional. 

Upon hearing of this, the students produced 1000 t-shirts, which they planned to wear to the next football game. The front of each shirt showed the school’s initial, a cross, and the words “I still pray...” On the back it said, “In Jesus’ name.” The ACLU asked the principal of the school to honor the free speech of these students who wished to protest against the ACLU at the football game. 

The Executive Director Kent Willis says; "Religious liberty demands that the government not impose religious views on anyone, and free speech demands that the government allow individuals to express their views." This means that while the school can’t permit the sectarian prayer over the public address, they also can’t stop students from peacefully protesting the efforts to stop the prayers. 

The ACLU hopes that this entire phenomenon will give the students and the school insight into the importance of constitutional principles and how they are applied to real-life. 

(Source)