using Ruby or Python, does someone know how to draw on the screen, covering up any other window?  Kind of like, press a key, and the program will show current weather or stock quote on the screen (using the whole screen as the canvas), and then press the key again, and everything restores to the same as before?  (like Mac OS X's dash board).
You could use the systems dashboard (desktop widgets, or whatever it's called) API. In order to do that you need bindings to it for Python or Ruby.
Alternatively you could use some generic gui toolkit or application framework and just create a frameless window with transparent background. Then you need to be sure that the chosen toolkit supports 'always-on-top' options on your desired platform(s).
does someone know how to show content on screen (covering up any window) using Ruby or Python?