The Pong Clock screen saver was written with Visual C++ 6.0 using MFC as a dll (so you'll need MFC42.DLL).
You can grab just the Pong Clock screen saver (.scr) file here. Note that this is the version which is running in the frame so

• it looks best at VGA resolution
  
• clicking a mouse button brings up the A-B interface (it doesn't terminate the screen saver)
• moving the mouse doesn't terminate the screen saver
• (but pressing a key does terminate the screen saver)

Update: September 17th 2008
This was originally written just for me, but others are finding it useful too, so some additional features have crept in :-)

• moving the mouse now does end the screen saver
• the size of the ball is now proportional to the screen size
• there's an additional "Configure" item in the A-B interface dialog
• with it you can choose 12 or 24 hour mode for the time display (12-hour is the default)
• you can also choose a Small, Medium or Large ball size, which corresponds to 1%, 2% and 3% of the screen height (Medium is the default)