What Is The Silliest/Most Ridiculous Coin You Have In A Slab?

I don't have any in my possession, but I've seen a few over the years.

The grading companies usually give you some kind of quantity discount deal. Platinum-level PCGS "membership" comes with 8 free submissions, for example. If you only have 6 coins you really want graded but you're entitled to send in 8 for free, are you going to let those 2 "spare slots" go to waste? Or will you simply pick up two random coins you happen to have lying around the house and toss them into the submission bucket?

Or maybe a bulk submission: suppose sending in 100 coins lets you apply for a cheaper rate, but you only have say 80 coins ready to go in for grading; it turns out to be cheaper to just toss in 20 random extra coins and get the bulk discount.

That, I suspect, is where a large proportion of the "why would anybody bother slabbing this" coins come from.

Finally, there's the "taking people too seriously" issue. Many a time, when someone comes onto the coin forums with a damaged not-really-a-mint-error coin, people will (jokingly) tell them to send it in to a TPG and see what they say. And sometimes - not always, not often, but sometimes - somebody actually does just that, and sends in a worthless damaged coin to get slabbed.