Here is a Minecraft Creeper model with a rotatable head!

Rotate the face upward for better print quality and no support needed. You may need to scale the pin up by 5-7% for a snug fit, especially if you print the pin holes horizontally. 3 perimeter layers, 3 top/bottom layers. Infill not critical.

Put a dab of grease on the pin for smooth rotation.

The pin design is based on http://www.thingiverse.com/thing:213946.

Enjoy!