Prepare a set of cards for class. Each card will have an answer and a question written on it.
As students come to class, hand each of them a card.
Keep one card for yourself and hand out the remaining cards to students who wish them. Then, beginning with your card, read the "I have ..." part and then the "Who has ... " part. The student who has the answer to your question will then read his or her card. The student with the answer to that question reads his card and so on until you have gone through the entire set of cards.

This is a good technique for reviewing for a test. It gets every student involved.

Below is a set of I Have ... Who Has ... cards to use with a review of the basic integration formulas.