When I was a foreign student in the US, my first ever credit card was Discover. I and my wife applied online. Due to some glitch in their systems, they started sending us two new cards EVERY DAY. I don't remember now, but I think the numbers were all the same. They only fixed the glitch in two weeks and cancelled all the cards. With scotch tape I built a large house of cards on my desk. Still funny.

Oh, and when I built a good credit history and had many cards, I maxed balance during interest free period and invested in US savings bonds for a year. )