Any apps to display time, temperature and a message on a TV alternating?

[newdeal]

So you know those signs that some businesses have that will tell you the time and the temperature and then might have some sort of message that scrolls across the screen? Well they are very expensive signs, I was wondering if there is an app that does the same thing that will output to a TV screen that you could have in the window of a store front to accomplish the same thing for a lot less money? It tends to draw peoples eyes to the store and I assume the app would be easy to make so it might already exist and I was hoping someone could point me in the right direction