A ram to sacrifice instead.

I am on vacation for one week celebrating with muslim Brothers

"Festival of Sacrifice" or "Greater Eid" is an important religious holiday celebrated by Muslims worldwide to commemorate the willingness of Abraham (Ibrahim) to sacrifice his son Ishmael (Isma'il) as an act of obedience to God, before God intervened to provide him with a ram to sacrifice instead.

 http://en.wikipedia.org/wiki/Eid_al-Adha