South Park Episode 403 - "Timmy 2000"
There's something wrong with new student Timmy.
About the only thing Timmy can do is say his name. Ignorant of the fact that Timmy is "retarded" they believe he has ADD, which relieves him of the responsibility to do any homework. Soon the rest of the class manages to get diagnosed with ADD, and all get prescribed Ritalin. Everyone is on Ritalin and just complacent enough to sit through a Phil Collins show.