A cow, a bull and an umbrella walk into a bar...
Okay - since no one took the bait, I'll try...
A cow, a bull and an umbrella walk into a bar. The bull orders two Gin Fizzes for him and his lady, and a double Gin Martini for the umbrella. The bartender and bovines laugh it up for half an hour as they keep downing drinks and regaling him with stories of their sailing adventures. The umbrella just sits there, looking down into his drink.
"Hey what's up with the umbrella?", the bartender asks, "He hasn't said a word."
The cow lowers her voice, "Oh, he rarely opens up."
(Okay, not as good as my historical "Two Trolls, a Monkey, and a Duck" joke. But it'll do.)