Leonard, Sheldon, Howard and Raj all come to the conclusion that they have been so distracted ever since the arrival of the girls in their lives that they have not been able to focus their minds on the matter of just brainstorming on issues scientific. So they decide to have a boys weekend in to do that brainstorming. They encounter many problems along the way, the two biggest being what to focus their scientific priorities on, and how to stay focused on the task at hand and not get sidetracked by other distractions. While the boys are in, Penny, Amy and Bernadette decide to have a girls weekend away in Las Vegas. Once they arrive in Vegas, a situation with Penny leads to a role reversal where Penny ends up being the studious one, and Amy and Bernadette end up being the drunken party girls.