In 1995, Patrick Combs deposited a fake junk mail check for $95,093 and the bank cleared it

In 1995, a San Francisco writer named Patrick Combs had $200 in his bank account. One day, he received a promotional junk mail check for $95,093.35. It said "non-negotiable" across the front.

According to Lisa Margonelli's 2002 article in SF Gate, Combs deposited the fake check as a joke, not expecting it to clear. Surprisingly, due to a series of banking errors, the check was processed, and the funds were credited to his account ten days later.

Combs became obsessed with monitoring his bank account, checking it every ten minutes to see if the money was still there. He did not spend any of the money. Eventually, he had the bank issue a cashier's check for the same amount, which he placed in a safe deposit box.

When the bank learned of the mistake, security personnel from the bank started to harass Combs to return the money. The bank also served him with legal papers in an attempt to prevent him from cashing the cashier's check.

From SF Gate:

By this time, though, Patrick was getting advice from everyone. He had put his story on the Internet and was getting letters from people daily, telling him to keep the money. "I realized that a lot of people were willing to set their values aside if the sum was large enough," he says. One guy said, "So what if you lose all of your friends. You'll have 95 grand and you can get new ones."

The money that had started as a joke became two new problems. First there was the ethical problem: was the money really Patrick's? And second, there was the legal problem: was it legally his? Ethically, Patrick couldn't ever quite justify keeping the money. "I kept coming back to the Robin Hood concept," he says, "I hate banks. How about if I take the money from the bank and give it to the needy? That's righteousness!" Still, the more he thought about Robin Hood, the more he was convinced that Robin Hood was wrong.

Combs eventually returned the money in exchange for a letter from the bank admitting to a series of mistakes on its part.

The experience changed Combs' life. He became a motivational speaker, and has presented at almost 2,000 organizations. Besides his speaking engagements, he engages in various social experiments involving money, challenging people to rethink their relationship with cash.

See also: How to make fire bricks out of junk mail