A tourist walks into a pet shop in silicon valley, and is browsing around the cages on display . While he’s there, another customer walks in and says to the shopkeeper, “I’ll have a C monkey, please”.

The shopkeeper nods, goes over to the cage at the side of the shop and takes out a monkey. He fits a collar and leash and hands it to the customer, saying “That’ll be $5,000″. The customer pays and walks out with his monkey.

Startled, the tourist goes over to the shopkeeper and says, “That was a very expensive monkey, most of them are only a few hundred dollars. Why did it cost so much?”

“Oh”, says the shopkeeper, “that monkey can program in C with very fast and tight code, no bugs, well worth the monkey.”

The tourist starts to look at the monkeys in the cage. He says to the shopkeeper, “That one’s even more expensive, $10,000! What does it do?”

“Oh”, says the shopkeeper. “that one’s a C++ monkey; it can manage object-oriented programming, Visual C++, even some Java, all the really useful stuff.”

The Tourist looks around for a little longer and sees a third monkey in a cage on its own with no price tag round his neck.

He gasps to the shopkeeper, “Why is that so! What on earth does it do?”

“Well”, says the shopkeeper, “I don’t know if it actually does anything, but says its a LISPER and of course priceless”