7.5/10. Lots going on in this one. First off, I appreciate how boldly the show committed to the weirdness of the parents thing. It's admittedly a particular sort of gross out humor, but the show went whole hog on it, especially the scene where Marshall's dad was awkwardly seducing Lily's dad, and I guess I can appreciate the fact that if you're going to go for such strange humor, you go for it whole hog.
In terms of actual stories, the weakest of them was definitely Barney trying to salvage his night with Nora despite the escalating misfortunes of a spill on the ice, a rat on her head, and suicide jumper in his building. It's a pretty unbelievably series of events without the balance of tone to make it work. And the fact that he saw his own mom in Nora but "turned it around" to deal with the problem was a weak resolution. That said, while it's a bit pat, the idea that Barney wasn't bothered by the comparison because he thinks his mom's great and thus the fact that his girlfriend is like her is a positive thing succeeds as nice coda for the whole theme of the episode. (Though, as Mrs. Bloom pointed out, Frasier did it first.)
Marshall trying to make Lily feel sexy during pregnancy is one of those relatable relationship stories that the show could do well, even if it goes off the deep end in the weird humor department. The parental comparisons were generally amusing. I was initially skeptical at the comparisons between Marshall and Lily's Dad, but the flashbacks to Marshall's various games did a nice job at setting up the connection. Plus, the swerve that Marshall explained how Lily is nothing like his mom, but then realized that she was like his dad was an amusing twist on the formula they were using.
The Ted/Robin/Kevin stuff was solid if not necessarily great. They're really exaggerating the Ted/Robin business, and Ted's patheticness to make the story work, which isn't a great choice. But Kal Penn is melding with the cast a little better than before, and his seeing Ted's fragileness and wanting to help resolves the story nicely.
Plus, the coda with Weird Al stealing 8 year old Ted's song idea was the kind of out of left-field tag that show's that the series still has a little of the absurd spark left. Perhaps not the best episode in terms of storytelling, but some quality, if out there laughs to be had.