Flood of calls

Today in-and-around 8:45 in the morning all of the phones in my office started ringing :). On all the phones (based on the few I checked) I noticed the call was from this # 66082763. It was the usual crappy advertisement call which I have never even bother to hear once in full :).

It was annoying at first with all the phones on your entire floor ringing one by one. But then I was a bit excited and was wondering if it was some sort of an cyber-attack or something :D. I remember a movie where all phones in a city starts ringing endlessly. He he, mebbe I should was less movies.

Anybody else faced this today? Any clue as to what caused this?