It isn’t likely to happen this season, but before Mad Men reaches the end of the decade, more than one member of the Sterling Cooper Draper Pryce family will turn on, tune in, and drop out. In our profile of John Slattery, we expressed the hope that Roger Sterling will take the maiden voyage down the rabbit hole. But Elisabeth Moss disagrees: She suspects Peggy will take the first trip. Not everyone on the show may experiment — most in Don Draper’s world skew Republican, except, perhaps Peggy — but seven have demonstrated a proclivity toward or a need for some purple haze. Here they are, ranked in ascending order of probability, and weighed on a scale of 1 to 10, with ten being the most likely.