This is one of those silly tricks kids love to do to impress their family. All you need is a piece of paper and a bit of dramatics (on the presenter’s part). Tell your audience that you can cut a hole in this piece of paper large enough to walk through. Maybe even have an assistant (who hasn’t seen the trick before) try and cut a hole in the paper. Then impress them with this amazing skill.
Cut the paper horizontally but not all the way through, alternating which side you cut from as you go down starting with the folded side ending with the same cut (starting on the folded end) as you started with. In the above photo the folded part of the paper is by his hands.