If you own one of Tesla Motors' Model S cars, you can control your electric vehicle with the new Tesla Command app that is available for Android Wear. Right now, the app has basic options, but it'll soon feature more.
The Tesla Command app for Android Wear allows Model S owners to lock and unlock their doors, open and close the sunroof, and it allow you to honk the horn, if that's what you want to do from your wrist. In order to get it working, you'll need to log in to Tesla online services, but once you're there you can do everything the app offers, all from your wrist.
You can gran Tesla Command for Android Wear from the Google Play store.