Noisy Paper

Fold a piece of paper in half.  Run one of your index fingers along the fold several times.  Unfold the piece of paper and tear the paper in half along the crease you just made in the middle of the paper.  Put the two pieces of paper on top of each other.  Put your lips on the edge of the two pieces of paper and blow.  (You can also do this with a folded piece of paper instead of two pieces of paper.)