Cool little stereo analog audio to PCM/Toslink converter from RadioShack. It was disco/deval down to $2.97 from $49.99. Found three of them. Got to love the Shack. Main use that came to mind was to use it to electrically isolate equipment. If lightning takes a radio it won't get to pc through audio link.

Being the firm good ground user I am I installed ground lugs to the ground plane on pcb. Had to cut little slots in case but not too bad to do. Copper plumber's tape works great for stuff like this.