Piyut are Jewish ritual poems recited during religious services. Piyut have existed since ancient times and are most often recited and written in Hebrew or Aramaic. They usually follow a specific poetic pattern often following the order of the Hebrew alphabet.
http://www.piyut.org.il/about/english/
http://www.jewishvirtuallibrary.org/jsource/judaica/ejud_0002_0016_0_15840.html
