Penny becomes addicted to an online game based on the world of Conan the Barbarian and persistantly pesters Sheldon for advice. This episode was really, really, REALLY good. It was so funny right from the begining straight through to the end. I loved the part where Leonard was on the game and Penny chopped his head off.
There where some really good recurring jokes where Sheldon and Penny where together and Leonard thinks something is going on between the two.
All in all this was by far one of the best episodes yet of The Big Bang Theory. I give it 9.5 out 10.