iDoorCam. . It's WiFi-enabled, and contains a button, day- and night-vision camera, microphone, speaker, and motion sensor, letting you see and communicate with whoever rings your door. It pairs with an included iOS app, letting you monitor your door from inside your home, at the office, or away on vacation, so you can choose whether to interact, or just let it ring.
It's a little sci-fi, a little retro, and 100% cool. Gear-operated and powered by a single D-cell battery, this Steampunk Clock has a flip action every 60 seconds. A perfect addition to your modern industrial or steampunk loft.