Slap your knees

A man goes walking in the forest. Like me, for example, walking in a national forest in the west, huge and wild and unspoiled. So the man goes walking. I go walking through the forest, I turn a corner--and I run into five hundred thousand of my countrymen who are walking and crying inconsolably, like children. I stop and I ask them why they're crying. And one of my countrymen looks up and says because we're all alone and we're lost.

The above is a joke, mutatis mutandis, from a brilliant passage in Bolano's "The Savage Detectives." Not exactly the kind of joke that makes you laugh out loud, but there's something to it, wouldn't you say?

Here's a kindred joke, from Martin Amis by way of Zadie Smith if I remember correctly:

Birth is when two people go into a room and three come out. Death, on the other hand, is when a person goes into a room and no one comes out.