Have you heard Patrick Combs' story? He deposited a fake check that he received in junk mail as a joke. Unexpectedly, the check, for $95,000, cleared and the balance appeared in his account. He waited for the bank to call about the mistake, but the call didn't come. Eventually he went to the bank and asked if he could spend the money. A manager assurred him that the money was legally his, since the waiting period for bouncing a check had passed. Combs went to a law library and learned that, not only was it too late to bounce the check, it wasn't an invalid check at all! The words "Not negotiable for cash" were printed on the check, but some nuance in the Uniform Commercial Code stipulated that this alone did not make a check invalid. He ended up talking to some retired expert who wrote the book on check law, who convinced him that the money was legally his. There followed a long standoff between Combs and the bank. He did not intend to keep the cash, but refused to return it without a written apology. It was a long and interesting story which he used to have posted to his website. He has since written a book and built a career as a motivational speaker telling the story, so now it's just a short version on his site: