Another old one, but still pretty funny.
"Hello, is this here the Sheriff's Office?"
"Yes. What can I do for you?"
"I'm calling to report my neighbor, Virgil Smith. He's drillin' holes in his firewood and hiding marijuana inside!"
"Thank you very much for the call, sir."
The next day, the Sheriff & his deputies descend on Virgil's house. They search the shed where the firewood is kept. Using axes, they split every piece of wood, but find no marijuana. They sneer at Virgil and leave.
The phone rings at Virgil's house. "Hey, Virgil! This here is Floyd. Did the Sheriff come?"
"Did they split yer farwood?"
"Happy Birthday, buddy!"