Last night was a plot-driven episode filled with crazy antics at the Natural History Museum: Lily and Marshall fight about adult problems, Ted and Zoey share romantic glances, and Barney and Robin get crazy and defy "Do Not Touch" signs.

HIMYM Breaks Rules at the Natural History Museum, Including "Do Not Touch"S

First up, was Barney and Robin's Tour de History. Barney "accepts the challenge" to not touch anything in the museum, and immediately fails. Then Robin gets in on the action and things spiral into a montage of them pushing the museum's limits. To be fair, I'd probably open a beer from an animal's mouth if I were in their shoes, too.

Eventually, they're apprehended and in the process of being interviewed by the Museum cop, Barney's real father is revealed. So, who do you think will be cast to play Barney's Uncle Jerry/Dad? We're excited to find out.

In another storyline, Marshall and Lily's rock-solid relationship hit a rough spot when Marshall revealed that he wants to take GNB's up on their offer of a 5-year contract. Lily, however, yearns for "College Marshall", who wanted to defeat the bad guys with his lawyer-dom and smoked lots of "sandwiches." The clip below is of the college flashback and then Lily's conversation with a real-life version of "College Marshall."

And for those of you who don't think that the writers are planning on making Zoey the mother because she's married...