GetTheWeather is a simple application I put together in Python using the Twitter API (facilitated by Twython).
It works like this: Simply send a tweet with your location enabled (geotagged) to @GetTheWeather on twitter and you'll get a reply with the weather or forecast in your area within a minute!
This was the first in a series of Twitter projects I intend to do which involve providing the user with the information they need in a timely manner on a platform they are comfortable with and using often.