Wearable devices have become very popular of late and Android Wear is fully incorporated into the Android SDK. The setting up of a Wear project is slightly more involved than other projects as wearable devices really act as a companion device with the apps themselves running from a mobile device.
Despite this minor level of complication, developing for wearables can be a lot of fun, not least because they often offer us access to some cool sensors, such as the heart rate monitor.