Also called mountain oysters oddly enough.

A man goes into a Spanish restaurant and orders the delicacy. They are so delicious he returns the next week and has another order. Finishing he says to the waiter, "those were wonderful but why was the portion so small this time?" The waiter replies, "Senor, the bull he does not always lose." 

"Democracy is a pathetic belief in the collective wisdom of individual ignorance." - H. L. Mencken