I've forgotten the first name of Don' current wife.

Megan.

I'm not sure the episode lacked anything for her absence, but after it was over I felt it was odd she hadn't been in it.

She's the Lana of the show.

Jessica Paré's Recording of "Zou Bisou Bisou" From Mad Men Season 5 Premiere Now Available

The original version of Zou Bisou Bishou by Gillian Hills.

Megan strikes me as such an anachronistic name for the 60s. Was it popular in Quebec at the time or something?

Apparently that prank with the Young and Rubicon (Y&R) guys dropping water bombs on Civil Rights protestors was a real incident that the NY Times reported on.

One reason Betty wasn't in the episode is that they were working around January Jones' pregnancy.

I think the AVClub review has a complete misread of this scene:

When she goes home, the positions of the two from the shot in “Tomorrowland” are reversed: Now, Megan’s the one laid low, while Don has all the power As she cleans in her underwear, telling him he can’t have her, he strides forward, dominant side returning to the surface. He grabs her by the hair, and there’s the slightest moment where you fear he might do something awful, before she consents. He “wins,” even if the pillow talk is all about how much they love each other. At the same time, she “wins,” because she gets to taunt him childishly and rile him up, even if it’s a hollow victory.

To my mind, Megan is manipulating Don in that scene just like a paid dominatrix, playing to his kinks for their mutual satisfaction. He's so filled with self loathing that he doesn't deserve a beautiful white carpet - it's much more arousing to be soiled and on the filthy carpet. She's not angry when she starts to clean up in her underwear; she's purposefully provoking him knowing what response she'll get.

To my mind, Megan is manipulating Don in that scene just like a paid dominatrix, playing to his kinks for their mutual satisfaction. He's so filled with self loathing that he doesn't deserve a beautiful white carpet - it's much more arousing to be soiled and on the filthy carpet. She's not angry when she starts to clean up in her underwear; she's purposefully provoking him knowing what response she'll get.

Yeah, I thought it was pretty obvious that they were playing out a scene. Surprising that AVClub didn't see it.

I read it the way they saw it, but I can see that way too.

If it wasn't clear from the scene itself, look at Don's reaction when Peggy told him that Megan had gone home to be alone - he (and we) knew that Megan was pissed at him for not having sex with her the night of the party, CLEARLY he was going home for a booty call.

I thought she was pissed at him for not liking the party at all ("Who doesn't want a surprise party?") and not being in any way grateful, and he was going home to try to make up with his wife.