Near the end of the episode, Penny and Leonard are having a conversation about Penny's life being exciting right now. She mentions that a psychic at a bachelorette party told her she would be a movie star. In season 3, episode 12, the Psychic Vortex, Penny and Leonard have a fight about psychics being real. In this episode, Leonard makes no comment about Penny's belief in psychics.
When Amy plays the Star Spangled Banner (minus the ending) on an electronic piano keyboard intentionally to frustrate Sheldon's need for closure, and later when Sheldon returns to finish the music on the same keyboard, they play the keys for A major, while the viewer hears the song in G major.
Sheldon says that the canceled show Alphas ended with "...all the residents on New York either dead or unconscious." This is not even close to how it ended. The ending was all the people who were in Grand Central Station were unconscious - except for Gary Bell - and the audience knew that all Alphas would be alive and enhanced, and were not sure as to the fate of the ordinary humans. Everyone else in the world was unaffected, as the team had successfully shut down the power grid.