It's a J1772 plug -
SAE J1772 - Wikipedia, the free encyclopedia
The Nissan Leaf and other new EVs and hybrids such as the Volt and Plug-In Prius are supposed to use the J1772 plug. Charging stations are being installed in many areas; most have the J1772 plug, and some also have a standard 20 amp/120 volt plug for EVs that don't have a J1772 style interface.