If you've never seen Get Smart then you'd know the Cone of Silence is a common joke where the cone doesn't do anything. It leaks soundwaves like a sieve. So in the Saddleback church forum where the candidates discussed their love of pixies. The point of cone of silence is to allow everybody to hear em.
There's some pretty strong and fun suggestions that McCain had a heads up on the questions. Which is a great talking point if you want to gloss over the fact that he was in a very pro-McCain situation and not want to focus on the subjects of the debate. Which to Obama was just to state repeatedly that he was Christian.