http://en.wikipedia.org/wiki/QurbanQurbani comes from the word Qurban. It is related to the Hebrew word for Temple offerings (Korban). I guess Muslims bring offerings to Allah wherever they feel like. I've heard of them killing camels as a form of thanksgiving offering. I think they did it when King Hussein came back to Jordan to make his son the Crown Prince before he died of cancer. They pretended King Hussein was healed and I remember reading about them offering their camels as a form of thanksgiving.
This is what Wikipedia says about Muslim sacrifices. I guess they don't follow their own laws.
Animals bought with the intention of sacrifice but were not slaughtered by the 12th of Zul Hijja should be donated 'alive' to charity.
Important considerations before sacrifice[edit]
The hair and milk of a living sacrificial animal may not be used before sacrifice
The animal be treated humanelyA spacious and clean enclosure be provided for the animal
The animal must be given adequate feed
The water to the animal be changed three times daily
Live animals must be kept out of view of the slaughtering area
The slaughter area has to be clean
Dragging the animal is not allowed
The knife for sacrifice has to be sharpened to the optimum, and the slaughter should be carried out quickly and effectively to minimise the suffering sustained by the animal. Sharpening is not allowed in front of the sacrificial animal. Muhammad saw a man who was sharpening his knife after laying down a sheep to be slaughtered. Muhammad rebuked him saying: Do you intend to make it die two deaths? Why did you not sharpen your knife before laying it down?
The correct size knife has to be used to slaughter the animal swiftly
It is preferable for those intending sacrifice not to cut hair of their bodies or clip their nails from the 1st of Zul Hijjah to after the sacrifice of their animal.
The actual sacrifice and method of slaughter[edit]