Rob Bell at Greenbelt last year (free download here - about 45 mins into the talk).
It is part of a question and answer session that I didn't hear at the time, but which having listened to it in the car has made a big impression on me. He was asked what he did, but rather than answer the question he challenged us all to think what it was that we "had" to do - that was what we should stop doing on our Sabbath. As an example he switches his mobile off and doesn't answer email on his Sabbath - now there's a thought! He said that his wife has her life run by lists - so for her the Sabbath includes no lists.
So what is it for me? I think the computer definitely stays switched off, and the mobile would if it were an issue, but it is so often a blessing for meeting up with people. One of the implications of this is that there will be a blogless day (Saturday), perhaps more as a symbol than anything else, but I believe a good one nonetheless.