Got this today via email -- an old chestnut:

The IRS decides to audit Ralph, and summons him to the IRS office.
The IRS auditor is not surprised when Ralph shows up with his attorney.

The auditor says, "Well sir, you have an extravagant lifestyle & no
full time employment, which you explain by saying that you win money
gambling. I'm not sure the IRS finds that believable."

"I'm a great gambler, and I can prove it" says Ralph. "How about a
demonstration?"

The auditor thinks for a moment and said, "Okay. Go ahead."

Ralph says, "I'll bet you a $1,000 that I can bite my own eye."

The auditor thinks a moment and says, "No way! It's a bet."

Ralph removes his glass eye and bites it. The auditor's jaw drops.

Ralph says, "Now, I'll bet you $2,000 that I can bite my other eye."

The auditor can tell Ralph isn't blind, so he takes the bet.

Ralph removes his dentures and bites his good eye.

The stunned auditor now realizes he has wagered and lost three grand,
with Ralph's attorney as a witness. He starts to get nervous.

"Want to go double or nothing?" Ralph asks. "I'll bet you $6,000 that
I can stand on one side of your desk, and pee into that wastebasket
on the other side, and never get a drop anywhere in between."

The auditor, twice burned, is cautious now, but he looks carefully
and decides there's no way this guy can manage that stunt, so he
agrees again.

Ralph stands beside the desk & unzips his pants, but although he
strains mightily, he can't make the stream reach the wastebasket on
other side, so he pretty much urinates all over the desk.

The auditor leaps with joy, realizing that he has just turned a major
loss into a huge win. But Ralph's attorney moans and puts his head in
his hands.

"Are you okay?" the auditor asks.

"Not really," says the attorney. "This morning, when Ralph told me
he'd been summoned for an audit, he bet me $20,000 that he could come
in here and piss all over an IRS official's desk and that you'd be
happy about it."