Back in 1984, I decided to test an unusual "honor system" of program licensing. I had Morris Jones (a member of my Cyber Privateering Fantasy League Team) write a little piece of software for the IBM PC. The program licensing agreement had a clause that said, "If you make unauthorized copies of this software and do not send us the $30 within 30 days, we will own your eternal soul and may sell it to the first Smoking Blood-Drenched Apparition With Fangs (SBDAWF) that meets our price." Interestingly, over the next year, we received lots of checks in the mail from people who didn't want any SBDAWF showing up to collect their souls. The Wall Street Journal even did a little piece on it.
I got the idea from my college days, when I met my first atheist. I told him he wasn't really an atheist and I could prove it. He got all huffy and challenged me, so I pulled out two quarters, fifty cents, and said, "If you're really an atheist, then sell me your soul for four bits. Since you're absolutely sure you don't have one, you make infinite profit, and there won't be any higher power in the picture to enforce the deal."
He sold me his soul, but by the end of the semester he was begging me to sell it back to him. Turns out, he didn't want to take any chance. My atheist friend was really an agnostic. I made enough money on the sale to get me home for Christmas.
I've met only one true atheist since then, and currently own his soul. Every Christmas, I let him know it's still in…ah…good hands.