Calvin and Hobbes by Bill Watterson for November 13, 1986
Calvin: I've got it all figured out, Hobbes. This play will be no sweat. Hobbes: You have all your lines memorized? Calvin: No, I thought I'd come out, do a little soft-shoe, and ad-lib something! Hobbes: Ad-lib something about dietary fiber? Calvin: Either that, or I'll do my onion mime!