Rock Paper Scissors Lizard Spock

If you have never watched "The Big Bang Theory" on CBS, you probably won't understand this t-shirt. The following excerpt is taken from Season Two, Episode Eight, "The Lizard Spock Expansion":

Raj Koothrappali: [Attempting to determine which Sci-fi show to watch the two heroes expand the rock-paper-scissors game] I'll tell you what. How about we go rock-paper-scissors? 
Sheldon Cooper: Ooh, I don't think so. Anecdotal evidence suggests that in the game of rock-paper-scissors, players familiar with each other will tie 75 to 80% of the time due to the limited number of outcomes. I suggest rock-paper-scissors-lizard-Spock. 
Raj Koothrappali: What? 
Sheldon Cooper: It's very simple. Scissors cuts paper. Paper covers rock. Rock crushes lizard. Lizard poisons Spock. Spock smashes scissors. Scissors decapitates lizard. Lizard eats paper. Paper disproves Spock. Spock vaporizes rock. And as it always has, rock crushes scissors. 

Makes me smile. If you want to find this t-shirt, please go to the Cafe Press store.