Don’t forget Humorous Speech Contest rule 6B!
Page 23 of the most recent Contest Rulebook has Rule 6B under Timing in the Humorous Speech Contest:
Time will begin with the first word uttered by the contestant.
However, should the contestant engage in definite verbal or
nonverbal communication with the audience (including the
playing of music or other sound effects, a staged act by
another person, etc.) prior [...]
