The character played by George Clooney in The Descendants is under pressure to sell extremely valuable Hawaiian land, which has been held in a trust for his family for over a hundred years. If he doesn't act soon, the trust will terminate and rights to the property will be distributed outright to dozens of family members. They might never agree among themselves on what to do with the property without expensive and extensive litigation.
Why will the trust end? The "rule against perpetuities"—the bugaboo of many a first-year law student.