Two of my faves:

A skeleton walks into a bar and tells the barkeep "I'll have a pitcher of beer, and a mop."
*********************

A piece of string walked into a small town on a hot, dusty day.
He was thirsty, so he sauntered into the first establishment he
encountered and asked the waiter for a glass of water.

"Sorry", said the waiter, "we don't serve strings here."

Discouraged, the string walked out. A little further down the
street, he met a stranger.

"You look hot," said the stranger. "Why don't you go into that
cafe and get a drink of water?"

"I tried that," said the string, "but the waiter wouldn't serve
me anything because I'm just a string."

"No problem" said the stranger. "I'll fix you up." He grabbed
the string, tied him in a bowline and frayed his ends. "Now try it."

The string slipped back into the cafe and asked the waiter for a
glass of water. "Hey," said the waiter, "aren't you the piece of
string that was just in here?"

"Nope," retorted the string, "I'm a frayed knot."