OneLessDrop is a custom designed cable holder being funded via Kickstarter.

From the description on the site:

In the time it takes to read this page, millions of power cords for mobile phones, iPads, and notebooks will slide off nightstands, side tables, and desks and fall to the ground. The global frustration created by this phenomena cannot be overestimated. This problem deserves an elegant solution.

$25 gets you one, $60 gets you three (one of which is red). Add $10 for outside U.S. shipping.