Card Off

Effect: A card escapes from a string.
Secret: A card and an envelope have a hole in their centre. The envelope is secretly prepared with a slit at the bottom. Put the card in the envelope but secretly push it part way out of the slit. This is hidden by your hands. Seal the envelope. Push the string through the hole. Secretly push the card back into the envelope. Ask two spectators to each hold one end of the string. Cut the bottom off the envelope and pull out the card. It seems that the card has penetrated the string by magic.