var keyFacts     = new Object();
    keyFacts.num = 1;

keyFacts.showFact = function () {
   var keyFact = 'key_fact' + keyFacts.num;

   new Effect.Appear(keyFact);

   setTimeout("keyFacts.fadeFact()", 5000);
}

keyFacts.fadeFact = function () {
   var keyFact = 'key_fact' + keyFacts.num;

   new Effect.Fade(keyFact);

   if(keyFacts.num == 5) {
      keyFacts.num = 0;
   }

   keyFacts.num++;
   keyFacts.showFact();
}