I have found this strange service. Read below, I am sure it will be usefull for some of us. The disadvantage thing is that its not a free service.

“Have you ever been trapped in a conversation with an annoying person and prayed that your phone would ring to give you “an out”?
Well, Ring4Freedom has answered your prayers!

Ring4Freedom is software that will ring your cell or desk phone at your command. Simply press the hotkey and your phone will ring instantly. Download Ring4Freedom now and say “hello” to the person calling you and “gotta roll” to annyoing colleagues, boring meetings, and uncomfortable conversations. ”

Source: Ring4freedom