This link gives you the Klingon translation of the Internationale and other stuff as well - very rousing, I have no doubt.

Here is the chorus:

   batlh may''a' Qav wIghobjaj,
   Qoy, be'nI'! Qoy, loDnI'!
   'u' choHmoHbej ghobmaj, --
   Hoch qo' roghvaH DIvI'.