On one of my last days at my old job, I was offered a look at one of our postage paid return envelopes that had been delivered back to our offices. Normally this envelope would be filled with very, very boring stuff.
Here is the envelope. Looks like the sender is a supporter of stopping breast cancer.
Here's the back. Puppy and kitten stickers!
Good old American porn.
I have done similar things with obnoxious mailings from credit card companies, except normally I just take the stuff out of one credit card application and switch it with the stuff from another. This was genius.
And it was real porn. I just arranged the pages so the really good stuff was face down. And I did not get excited by the content. I just had to go pee right afterwards.