The nostalgic hall of mirrors that has made this Seinfeld-reunion season of HBO’s Curb Your Enthusiasm such a gas—look, the Seinfeld guys are playing themselves as if they were characters on Curb—took on hilarious and ultimately satisfying new dimensions in Sunday’s season finale (titled “Seinfeld”) about a reunion show designed to correct a much-maligned series finale. It delivered the sort of happy ending that was anathema to the original Seinfeld series, which is why a revisionist faux-reunion finale was such an inspired hook for this seventh season. (Let it not be the last.)

“We already screwed up one finale. We can’t do another,” whines a puzzled Jerry as Larry, consumed by jealousy over Jason-as-George’s attentions to Cheryl, threatens to ruin the reunion show by rewriting the script, denying George and Amanda (the character based on Cheryl, who’s also playing the role) their happy ending. Basically, Larry is jealous of himself, of George (the character based on Larry David) as played by Jason Alexander, whose chemistry with Cheryl is getting under Larry’s infamously thin skin. Larry runs Jason off, leaving behind what Jerry Seinfeld calls “a three-legged goat.”

Larry’s horrifying solution? “I’ll play George!” If it had been my call, I would have titled this episode “The Second Darren.” As in: Darren Stephens #2 on the classic Bewitched, whose ghost Larry invokes to justify this terrible idea. “Nobody liked that second Darren,” Jerry says, braying the undeniable truth: “This is iconic television here!” Jerry & Gang? Icons? Larry? No-con. Jerry again: “There’s no John, Paul, George—and Larry. It’s not what they want.”

But secretly, we do want to see just how dreadful Larry would be as George, and we get our wish. He’s deliciously, deliriously terrible, every bit as uncomfortable to watch as Larry David often is in Curb’s more excruciating and ear-splitting moments. He’s full-throttle over-the-top, and when the boom is lowered, Larry walks off the show, setting up the happy ending for the Seinfeld reunion and the Curb season.

What we see of the Seinfeld reunion episode looks pretty classic, incorporating the bit about blowing one’s nose into a cloth napkin as a running gag, and the timely plot device of George losing his fortune from inventing the iToilet app to Madoff’s ponzi scheme. Elisabeth Shue has replaced Cheryl in the final cut, which comes as a shock to Larry, who’s watching at home. Cheryl’s at the door, with coffee from Mocha Joe (a very funny Saverio Guerra, Larry’s nemesis throughout the episode). Cheryl quit after Larry quit (having overheard his confession about doing it all for her from behind her tinted car windows), and as they watch the end of the episode together, Cheryl reflects: “They belong together.” And so, despite it all, do Larry and Cheryl.. Even if she is the one responsible for the watery ring stain on Julia’s antique table, the farcical capper that resets the clock on their exasperating relationship.

All that, and solid jokes about Jason’s pamphlet/book “Acting Without Acting,” everyone’s respect (or lack of) for wood, a shout-out to the classic comic duo of Richard Benjamin and Paula Prentiss (anyone else out there remember He & She?), and a series of riffs on the expression “Having said that…” The last two episodes of Curb were like a season unto themselves, and it doesn’t get much more pleasurable than that.

Having said that, Curb wasn’t the only hour of TV that sent me to bed on an over-stimulated high. Showtime’s Dexter offered up a Thanksgiving-themed hour that stuffed a number of shocking reveals into its rumination on the nature of seemingly happy families that just happen to harbor a serial killer. Dexter is adamant he hasn’t poisoned his family the way Arthur Mitchell aka the Trinity Killer has done to his own picture-perfect clan, who all turn out to be terrified and abused prisoners of this mercurial psycho.

But Dexter is probably fooling himself, which ghost-of-Harry knows all too well. As Dexter wonders about Arthur, “What kind of father keeps a coffin in his garage?” Harry retorts, “What kind of father keeps blood slides in his shed?” Said shed is violated by little Cody falling through the skylight while Dexter/Kyle is playing Thanksgiving spy at the Mitchells. Dexter can’t afford to have those walls tumbling down, especially after he’s seen the havoc unleashed at the Mitchell domicile. “Is anything really safe here?” Harry needles him.

Maybe not, given that Rita’s neighbor has just made a pass at Dexter’s neglected wife, casting a pall over the Morgan family feast. (Nearly everyone’s distracted: Matsuka is unnerved, having inadvertently spied on the kiss, and Deb has just had a breakthrough about who shot her and Frank.)

The night’s centerpiece is the visceral blow-up at the Mitchell house dinner table, which the episode has been building toward with ominous inevitability as we marvel at John Lithgow's masterful Jekyll/Hyde portrayal of family man/monster Arthur. He berates his golden-boy son Jonah, trashing his baseball trophies and hounding him out of the house, causing the boy to snap and do damage to dad’s vintage car, for which there will be payback later in the form of a broken finger while watching the big game. Things are maybe even worse for adolescent daughter Rebecca, who’s locked in her bedroom until dad sees fit to let her out. Confronted by Dexter, the confused teen comes on to him sexually, while begging Dex to “get me out of here.” (It wasn’t until after the episode that I realized this is the same actress who caused me such agita when she appeared on Gilmore Girls as Luke’s surprise daughter, April.) Arthur’s wife, understandably, is a total basket case.

It all comes to a head as Arthur, carving the turkey, asks everyone to say what they’re thankful for and no one mentions him. He doesn’t take that very well, leading to a screaming knockdown with Jonah (who breaks the vase containing the ashes of Arthur’s beloved sister Vera). As Arthur chokes Jonah, Dexter loses control and wraps a belt around Arthur’s neck, dragging him off the boy and onto the floor, pulling him into the kitchen, where he threatens him with a handy butcher knife until the family interrupts, horrified by this killer-on-killer spectacle.

Cut to Dexter driving away in a fury, as Harry taunts him: “You showed Trinity the monster in you.” Dexter doth protest too much that he’s nothing like Arthur, and his family is nothing like the Mitchells. Michael C. Hall is pretty brilliant through all of this.

As it turns out, Arthur has another offspring we haven’t been aware of, but which dovetails with Deb’s brainstorm about the pesky reporter who’s been sleeping with her partner, Quinn. (Does this precinct have bad taste when it comes to bedmates or what.) How did Christine, the crime reporter, know that Deb was watching Frank take his last breath as she lay fallen? Because Christine was the shooter. Not only that, but she’s Trinity’s daughter. Didn’t see that coming. (But it does help justify what up to now had seemed like a pointless and boring subplot. There’s still no redeeming the Laguerta-Battista office romance.)

Only three more episodes to go, which makes me wonder if Dexter’s big finish this season will take place around Christmas—which would be fitting, given how central the theme of family and ritual traditions has been all season, as Dexter continues to struggle with satisfying his dual responsibilities to his Dark Passenger of death and the life-force of the loved ones who depend on and threaten to redeem him. Happy creepy holidays, y’all.