Headache

Me:  "Today I have a giant headache, so I do not mind if you work together to complete the worksheet, but please keep the noise level down."
(Most students shaking their heads in acknowledgement)
Student (screaming):  "YEA, SO BE QUIET TODAY, MRS. A HAS A HEADACHE!"
(Silence)
Me:  "Thanks for your help in quieting everyone down."