Quoctrung Bui

In a classic bubble — as we've seen in housing, tech stocks, or Beanie Babies — the fun ends in a crash. Things go belly up, and people can lose a lot of money.

The creators of the collectible card game Magic: The Gathering faced such a bubble. The cooler they made their cards, the more the resale value increased — and threatened to send Magic cards the way of the Beanie Baby.