How about how you got caught plagiarizing? It should be a hoot!
Frankly, I am amazed that you had the courage to ask again.
Funny is mainly in the delivery, not the content. Pauses, facial expressions, mannerisms. Watch Leno, or Letterman. So my point is that you need to pick any subject, use some sarcasm (or like), but work on the delivery. I suspect that is the point of the speech assignment: delivery.
Videotape yourself, and critique. One of our tutors is a comedian, and he practices, practices, and practices. Acually, there is a great deal of practice in speech giving. Little things like body movements, hand or head gestures, count greatly.
But in comedy, watch Leno: hands, pauses, face, and timing. Mimic his style.
thank you very much