Of course, if someone says, "Stop," you have to respond with, "Hammer time!"
Similarly, if someone asks, "What time is it?", the correct answer is: "Four-thirty!"
I read somehwere, a long time ago, that the "4:30" in the Spin Doctors' song, "What Time Is It?" refers to the time of day that factory workers in America would traditionally clock off on a Friday afternoon. I seem to recall that refering to something as "4:30" meant that it was broken, faulty or substandard in some way - somewhat similar in connotation to the "Friday car" referred to in the UK when someone has a car that repeatedly develops faults.
However, I cannot now find any such reference to this vernacular on the interwoop. So maybe I dreamt the whole thing.