" The Justice League Recombination " is the 11th episode of the fourth season of , which originally aired on December 16, 2010 . The episode centers on the group's attempt to win a New Year's Eve costume contest at the comic book store by recruiting Penny and her dim-witted boyfriend, Zack, to complete their Justice League lineup. Episode Summary
The group's Justice League configuration for the contest includes: The Justice League Recombination - IMDb [S4E11] The Justice League Recombination
The boys encounter Penny's boyfriend, , and are surprised by his lack of scientific knowledge (such as mistaking an atom for a planet). Despite mocking him initially, they realize he is their best chance at winning a costume contest as he has the perfect physique to play Superman . Penny is reluctantly roped into joining the group as Wonder Woman to ensure they have a complete, high-quality team. " The Justice League Recombination " is the
On New Year's Eve, the group wins the contest, but the victory is bittersweet for Penny and Leonard, as they realize they both still have lingering feelings for each other despite her current relationship with Zack. Despite mocking him initially, they realize he is