Great idea...

Just watched the beginning of Countdown, and Carol Vorderman came up with a champion idea. When you get one of those really annoying cold calls from someone trying to sell you something. Tell them to hold on a second and put the phone to one side and don't go back to the phone until they have hung up. It will waste their time and money and hopefully they will never call again.

Give it a go, you know you want to.