What is 20-minute Lull?
The phase in any conversation, usually occurring every 20 minutes or so, where the conversation gets quiet and no one really knows what to say. This is the point in the conversation where everyone involved will be desperately fishing for topics and might take up talking about the weather.
"So.... how about that... err... I don't know what to say."
"Me either... we must've hit the 20-minute lull."