Here's how this situation went down, George wanted to check out how Common was on the court for real so he challenged him to a game of horse. When they came back from break George said he hurt his shoulder warming up, so he had to have a replacement fill in for him. Common was thinking he was joking, and no one would replace him. Then George was like here is my replacement Brandon Jennings, and Common's eyes got real big. It was funny how surprised he really was, and it's something you have to see to enjoy. George Lopez also thought it was the greatest thing ever, how when they started playing the game they both kept making shots.
This link should take you to the video to check it out.