Tomato, Tomahto

On the first day of class, Himself tells his students to keep their cellphones off.

Himself: I don't mind if your cellphone is on, but your classmates will. Your phone will go off at the most important part of the lecture. What I do mind is your taste in music. So phones off.

Student: So what kind of music do you listen to?

Himself: Mostly 50s and 60s.

Student: Ah, Roots