Dayenu Madness
  Attribution: Unknown

After each verse of Dayenu, leader announces how the chorus is to be sung.
Some examples:
  Only women
  Shouting
  Those over 65
  Whispering
  While leaning to the right
  Men under the table
  
Another variation has each line sung to a different melody.
Some examples:
  Happy Birthday
  Frosty the snowman
  You are my sunshine
  Daisy daisy
  On top of spaghetti

We've sometimes drawn slips with the suggestions out of a hat, with one or more
slips saying "Participant's choice"