Sarah Chalke and Josh Radnor

On TV, it's all about living up to expectations.

Sarah Palin and Saturday Night Live certainly achieved that in this weekend's instant-classic and rabidly anticipated guest appearance by the controversial Republican vice-presidential candidate on the resurgent (though still woefully uneven) late-night comedy show. Watching Tina Fey impersonate her from a backstage monitor, palling around with Alec Baldwin (in GOP terms, the next best thing to a celebrity terrorist), throwing the "Live from New York" opener after crossing paths all-too-briefly with Tina, bopping to Amy Poehler's rap groove at the Weekend Update desk, the good-sport Alaska governor no doubt did wonders for her own approval ratings (or at least her TV "Q" ratings) while boosting those of SNL.

So what else is living up to the buzz?

Tonight, top honors in that tough Monday-at-8 pm/ET time slot goes to CBS's How I Met Your Mother (8:30), with a terrific and pivotal episode that finds Ted Mosby (Josh Radnor) — whom one character pointedly refers to as "the most romantic guy I know" — impulsively taking up fiancée Stella (the sublime Sarah Chalke) on her "spontaneous" offer to submit to an instant wedding, after her vegan sexpot sister's own ceremony falls apart at the last minute. No real time for pre-wedding jitters, except when it comes to bringing back Robin from Japan, where her new TV gig predictably is going less than swimmingly. Barney can't wait to see her and rekindle his crush, but Stella's not as keen on an ex intruding on her big day. What happens next? I'll leave that for Future Ted to put into context. But if you're even a casual fan of this underrated comedy, you won't want to miss it.

Finally, can we talk Mad Men for a bit? The brilliant second season's penultimate episode aired Sunday, and just like in the glory days of The Sopranos, when you could always count on the next-to-last episode to deliver the goods, this hour was a knockout, more than exceeding our expectations for a show still basking in its Emmy glow, if not with commensurate ratings. (For Adam's full recap of the episode, click here.)

It was disturbing: Joan's rape by her golden-boy doctor fiance on the floor of her boss's office, Greg's appallingly ugly attempt to show her who's boss and to establish his dominance over her past sexual history (notably, this follows his introduction to her ex, Roger). By the way, nice shout-out, during Joan's earlier failed attempt to seduce Greg in bed, to sci-fi classic The Day the Earth Stood Still (playing on the "Million Dollar Movie"), the upcoming remake of which co-stars Mad Men's own matinee idol, Jon Hamm. But all together now: Run, Joan, run! Drop this creep! (Though for now, it looks like she'll be keeping up appearances.)

It was ennobling: Peggy, on the other hand, declaring herself to be one of the guys with her confident usurpation of Freddy's former office and wet bar, confirming her status as one of Sterling Cooper's players after landing the Popsicle account. Unlike in her Popsicle campaign, I doubt she has any plans to share her office with others.

It was intriguing: Betty still a case study in broken-marriage pathology, finally leveling with poor little Sally, after locking her in the closet for sneaking a smoke (who can blame her?), about why Daddy is away. And passive-aggressively calling former riding partner Sara Beth to taunt her about Arthur's impending wedding, after having set them up to have a fling. "There's a difference between wanting and having," scolds Betty, who knows from where she speaks. But still, what a troubled soul. (What's up with the bleeding? We'll find out in next week's finale.)

It was scintillating: Meeting Bert Cooper's sharp-tongued grande dame sister Alice, the only person allowed to wear shoes in his office, who advises her brother to accept the merger ("You are old … You're not well") and to "go visit his cattle." (Huh?) She knows the lay of the firm's land all too well: "Let Roger Sterling have what he always wanted: to die in the arms of a 20-year-old." Loved her! And with Don still officially "under the weather" — I can't believe no one's raised a red flag of alarm in his absence — the merger with the London firm is approved.

And ultimately, it was riveting: Don's further retreat into his Dick Whitman persona, reliving (through a series of flashbacks woven into a present-day reunion) his relationship with the first, and true, Mrs. Don Draper: Anna, the widow of the dead officer whose identity Don/Dick assumed. Hamm has never been better than in these scenes with Anna, appearing almost puppy-dog boyish in her company. "You can be my cousin," he grins after telling her, in a flashback, he'd fallen in love with Betty. She is the compartment of his life that we have never seen, and she's still a significant symbolic other. (She was who he sent the poetry book to in the season opener, a book whose title — Meditations in an Emergency — gives next Sunday's season finale its name and theme, as events unfold in the shadow of an international crisis.)

The episode ends with Don/Dick walking into the surf, having been given Anna's blessing: "The only thing keeping you from being happy is the belief that you are alone." (A sentiment you'll also hear in different form this week's episode of Eli Stone, by the way.) He falls under the waves, a baptism and rebirth that will allow him to return, cleansed if not exactly clean, to the hallowed halls of Sterling Cooper and maybe even to the domestic non-tranquility of Ossining to pick up where Don Draper left off.