Here's my idea for a novel:

The Earth experiences a near-miss with an asteroid, which skims the surface of our atmosphere. Afterward, people notice that mergers and acquisitions attorneys are unusually ravenous. They begin biting people, who themselves, after a short illness, become mergers and acquisitions attorneys. Soon, it's not safe to venture out at night because the streets are filled with mergers and acquisitions attorneys hungry for human flesh (as in real life, sunlight is a natural foe of mergers and acquisitions attorneys). The world becomes consumed with their bloodthirsty howls and SEC filings as the human population dwindles....

Here's my idea for a movie:

A biological warfare program has an accident, and an airborne pathogen spreads across the world. It kills everyone who has gone through puberty. Once it kills off the adult population, the virus itself dies as it lacks proper hosts. Children are left to rebuild the world.

Alternatively, the virus kills 95% of the post-pubescent population, leaving only all the children and a few adults.

What's your idea for a novel? What's your idea for a movie?

Image credit: unknown, via David J. Batista.