Here is a cool drawing robot that can connect to the internet and draw and erase messages for you. The iBoardbot is capable of drawing and writing on a glass surface. You can send information to it from anywhere in the world. The web app can reproduce what you remotely draw.
The iBoardbot has an open API. It can be used to write tweets with a specific hashtag, show the weather forecast in your city, or display reviews for your business. It has text, drawing, and graphics mode. The robot is based on an Arduino board. You can find out more about it here.