"Let's table that topic for another time/conversation"
"Let's take this conversation offline"
Those are 2 ones that seem to come up on conference calls or emails with several people on that is basically code for either they don't want to answer a question or address the topic or they possibly want to limit who hears their response. Kind of a cop out at times when someone is put on the spot.
I personally try to use it in a context of "I don't want to waste everyone's time explaining a concept that everyone understands but you". I even have started saying "let's talk offline so we're not taking up too much of the meeting time"
