CodeSaver is a simple screensaver for Windows that can “type” the content of any text file on your screen when the computer is not in use.
The screensaver is open-source and the default setting is such it will display its own source code on the screen. Or, if you are in the habit of writing your to-do lists in text files, you can change the screensaver setting to that folder and it will print your pending tasks on the screen.
The publisher description says that the Code screensaver is compatible only with Windows XP but it works with Windows 7 just fine. Also check out the Wikipedia screensaver.