We had one walk into our office at like 5:30am. He wanted to sell us advertising space on a banner behind a plane. You could get a 2ftx1ft banner for free! But anything bigger would cost more money. There was also a consultation fee of $2.50. I mean, he was honestly pretty entertaining and non threatening. When he found out we were an engineering firm, he said "So you can build anything that ever was or ever will be." Not a question, that was his statement. The when we finally got him to leave, he said, "I think we've both learned from this, remember you can built anything! I should patent that..."