One hot afternoon two friends were out relaxing on the back porch.
"Would you like some iced tea?" one man asked his friend.
"Oh yes as long as it is good and cold."
The host then brought his friend a large glass of iced tea and dropped two small ice cubes in it.
His friend took a sip and remarked, "It's not very cold."
"Give it a minute," the host said.
The iced tea then appeared to start boiling. After a minute or so the ice melted, the boiling stopped, and the glass was ice cold.
The man took a sip and thanked his friend for the very cool drink.

So what made the iced tea cool in this unusual way ?