Today Slate launches a new series on the evolution of everyday design. We open the series with the key, explaining the history and development of those tiny slabs of metal that let us into our homes. Metal keys are ubiquitous today—and have been for centuries—but they are an endangered species as the world becomes increasingly electronic. In coming weeks we’ll tackle the phone, the fork, the paper clip—offering mesmerizing histories of the objects we take for granted each day.

Here’s where you come in: We want Slate readers to tell us which objects in their lives seem most mysterious and fascinating. Should we consider the flashlight? The eggbeater? The baseball cap? Please send nominations to everydayobject@gmail.com.