Via smart grid technology, you could plug your car and your home appliances into the electric outlet--and it would "talk" with electricity suppliers to arrange the most convenient or cheapest way to power your home.
Today manufacturers are meeting to agree on a standard plug for the home hub, cars and appliances.
BUT it turns out that American manufacturers already agreed on a standardized electric vehicle plug—in 1913! In the early days of cars, electric vehicles seemed a likely competitor for gasoline-powered engines and 30,000 were on the road; thus, the plug seen here, ca. 1913—complete with wooden handle.
Images found by Ted Bohn / Argonne National Laboratory.