According to this fan theory, first posited by Reddit user /u/numbertheory and picked up by Screen Rant, it's quite possible that Penny is secretly a spy. That's right — move over The Americans, because Chuck Lorre's got an entirely different story to tell about a deep cover agent living among her unwitting marks.
The theory ties into the notion that the federal government has been spying on Sheldon and Leonard ever since Leonard broke up with Joyce Kim (Ally Maki), a woman who was revealed to be a North Korean spy in the episode "The Staircase Implementation." An upset Leonard causes an explosion that takes out the building's elevators, which may not interest local authorities for very long but — coupled with the Kim incident — very well could have drawn the attention of the federal government. Aware of Leonard and Sheldon's knowledge of a rocket fuel project, they simply sent Penny in to monitor both men, according to the theory.
We know. It sounds absurd, but it actually ties up all of the lingering confusion about Penny's lifestyle. Think about it: Penny, without even an identifiable last name, has been sent into the men's lives to observe their antics. This explains why she spends so much time with two guys who don't share her interests, why she lacks any friends of her own, how she can afford an apartment without a roommate, and why there's a lack of traction in her so-called acting career. All obvious violations of Occam's razor aside, sometimes it's the explanation that actually explains everything that's worthy of consideration — unlike the real-life Big Bang Theory, ironically enough. You can think of it as a Unified Theory of Penny.
