The Two Friends
by by a 13 year old magician
This is my favorite trick done with sponge balls. You only need two of them. To perform, show the audience your two sponge balls, explaining that they are friends, and no matter what you do, you can't separate them. To demonstrate, get a volunteer. Fake pass one of the balls into one hand, while retaining the both in your other hand. Emphasize the "fact" that there is one in each hand, and have the volunteer hold out his hand. Tell him that he is to close his hand as soon as you give the one ball (really two) to him, or else the other one will magically jump from your hand to his and join the other, and the trick will be ruined. Hand him the two balls held together as one, and if he closes his hand quick enough, he will think that it is just one. Wait a second, then jump, as if startled. Then, roll your eyes and groan, "Oh no, you didn't close it fast enough!". Open your hand and have him open his. Let him and everybody laugh for a minute, then say, "I'll give you one more chance." Repeat the whole process, only this time give him none of the balls. Keep going like normal, and then glance down. Jump again, roll your eyes, and say "Ya lost 'em!". Walk away disghusted, and then bow to your thunderous applause.
A note on the patter. Do not think up a script, and repeat it. Then it sounds stale. I find it helps to think of the basics of what you'll say, then go along loosely with it. Also, don't make the volunteer feel bad. Once the kidding is done, thank him publicly: on stage, or during your street performance.
Good luck, and practice, practice, practice!