Joan dons blue eye shadow to match her dress on "Mad Men." Photo: Courtesy of AMC

It's only the third episode of "Mad Men," but the plotline -- both dramatically and sartorially -- already has us by the throat.

The Aug. 8 show was centered around New Year's Eve 1965, a year that would see U.S. combat troops enter the Vietnam War, Malcolm X's assassination, an intense space race with the Soviet Union, and the birth of the Grateful Dead and their hippie followers.

While many of the ladies of Sterling Cooper were away on vacation (and Betty was sadly nowhere to be seen), we did get a quick glimpse of Peggy -- in a drab blue and brown plaid dress with a cinched waist and ruffled front -- and Joan, who was spotlighted during the episode.

Still clad in her signature curve-hugging dresses and chic gold pencil necklace, Joan made one noticeable change, and it involved her beauty routine.

While bright coral and red lips paired with relatively tame eyes has been the go-to look for most of the ladies up until this point, in episode 3 Joan matched her peacock blue dress -- which featured a ruffle cascading down the hip -- with robin's-egg blue eye shadow worn almost to her eyebrow.

Of course, light blue eye shadow -- which is making a small comeback -- came to define the '60s and was seen in prominent beauty advertisements and smeared across the eyelids of Jackie Kennedy and Marilyn Monroe in Andy Warhol's famous pop art portraits.

In this episode, we also see the contrast between the sleek and chic style of Manhattan girls and the relaxed fashion worn on the West Coast when Don visits his ex-wife Anna (long story) and also meets her young niece, an opinionated political science undergrad at Berkeley who frolics around in high-waisted white shorts with bikini tops and loose-knit zip-up sweaters.

Another style highlight: the green sequined party dresses worn by some, well, working girls who accompanied Don and his co-worker Lane for the holiday evening. The girls' bouffant hairdos paired with the sausage-casing-like dresses made us dream about throwing a '60-style costume party, stat.

Keep reading for the lowdown on "Mad Men"-inspired nail polishes.