I took a break from studying by catching up on some episodes of "Better Call Saul" on Netflix, and came across a 12(b)(6) reference in Season 2 Episode 2, "Cobbler". If you aren't familiar with the show, it is a prequel spinoff from the "Breaking Bad" series and follows the story of small-time lawyer, Jimmy McGill (referred to as Saul Goodman in the Breaking Bad series), who pushes the boundaries of legal ethics throughout the series.
Around the 20 minute mark, Jimmy discusses a case regarding a retirement community contract dispute with one of his firm's partners. Jimmy noticed in the initial disclosures that the opposing party kept referring to an optional-allowance program, but none of the tenants had opted out and Jimmy thinks its more of a mandatory financial arrangement. Jimmy reasoned this to be a failure to state a claim that the opposing party filed in their answer because if the program is optional then it's voluntary, and if opting-in is a residency requirement then their voluntary claims hold no water because the program would actually be mandatory.
Essentially, Jimmy is saying that the opposing party's answer is factually insufficient by not providing enough facts to prove the plausibility that their claims are in fact voluntary. Jimmy understands that if his motion passes it will be without prejudice thereby allowing the opposing party to amend its pleading, but considering the importance of proving the claim's voluntariness this might be a tough task for the opposing party to accomplish.
There are other Civil Procedure references scattered throughout the series, but this show might be more appropriate for a Legal Ethics class discussion. However, if you need a break from studying I would highly suggest this show as an option.