my friend's dad told me this one:
A lizard is walking through the jungle when he looks up in a tree and sees a monkey in a cloud of smoke.
"What are you doing up there?" he says.
"I'm smoking a joint!" The monkey replies.
"No way! We cant get weed out here man!" The lizard says.
"Wanna bet?" says the monkey "Come up here and take a hit!"
So the lizard climbs up the tree and sits down next to the monkey and they smoke and smoke and finally the lizard stops and says "Man I'm STONED.
I gotta get a drink of water!"
The monkey tells him "There is a river down the way a little bit, you can get a drink there."
The lizard climbs down the tree and walks to the river, and he leans in to get a drink, but his balance isn't very good so he stumbles into the water and starts floating off down the river. An alligator sees him and grabs him and sets him back on the shore.
"What's wrong with you?" says the alligator "Why did you fall in like that?"
"I'm baked." says the lizard "I smoked a joint with monkey over there in that tree."
"No way!" Says the alligator, "We can't get weed out here."
"Don't believe me?" Says the lizard, "Go look."
So the alligator walks over to the tree and looks up at the monkey and the monkey calls down to him "Wow, man! How much water did you drink?!"