J.R. Martinez and Karina Smirnoff. (Adam Taylor/ABC)

After the troupe from the Broadway version of “Sister Act” wraps up, Tom Bergeron and Brooke Burke Charvet announce that this is an especially big night because it’s the first “group dance,” so we’ll get to see the levels of dance incompetence (at least, from certain people) side by side.

Reality star Rob Kardashian and Cheryl Burke

Dance: Cha cha to a “Jersey Boys” song

Rob has got all kind of confidence after getting a high score last week, and he tells Cheryl he wants to shake it like Maks. This is the second week in a row that Rob has mentioned idealizing Maks’s dance skills — who wants to break it to Rob that it’s never going to happen? Anyway, Mama Kardashian (a.k.a. Kris Jenner) stops by to get weepy and tell Rob that she never thought such a shy young man (again, he’s on about three reality shows, but who’s counting?) would ever be able to dance in public.

Rob and Cheryl wear matching red vests and perform hilariously cheesy moves. Rob looks like a robot but seems to remember all the steps. Len appreciates Rob’s moves but says he lacked rhythm. Bruno screams about Rob not having enough charisma, while Carrie Ann says it wasn’t as impressive as the dance last week. We get a shot of some disappointed Kardashian family members in the audience. Scores: 8, 7, 7 for a total of 22 points.

Commentator Nancy Grace and Tristan Macmanus

Dance: Fox trot to a “Monty Python” song

Nancy is not pleased that the judges told her she was “drab” last week. She shoots Carrie Ann daggers on the dance floor. “Do they want me to put on a bikini with spangles on it and shake my booty?” Nancy wonders. She demands more complicated choreography from Tristan, and when he does, she tells him it’s too complicated and that he’s trying to make her fail. “That’s the stupidest thing I’ve ever heard,” Tristan says, reading our mind.

After an entire clip package of her complaining, it’s amusing to see Nancy paste a frozen smile on her face and dance to the chipper “Always Look on the Bright Side of Life.” They throw in some high kicks, and though Nancy appears to forget a few steps in toward the end, it isn’t the worst dancing she’s done. Carrie Ann is impressed and calls it a showstopper, and Len still manages to criticize while saying he liked the razzle-dazzle. Scores: 9, 7, 8 for a total of 24 points.

Ricki Lake and Derek Hough (Adam Taylor/ABC)

Dance: Quickstep to “Grease” song

A clean-shaven David Arquette wants to maintain momentum from last week’s high scores and explains to us the deeper meaning of jazz hands. Yes, jazz hands have a deeper meaning (they represent enjoying life to the fullest, obviously). He has trouble catching his breath while practicing the high-energy dance, but since Ricki and J.R. are also dancing the quickstep, he’s determined to kick it up a notch.

With the goofy “We Go Together” tune, David goes through the routine hopping around and even flips Kym over without dropping her. Carrie Ann is thrilled, save for a few late steps. Len calls it rough around the edges, and his enthusiasm got the best of him. Bruno sums it up, saying David looked like a “frisky teenager on spring break.” Scores: 8, 7, 8 for a total of 23 points.

Talk show host Ricki Lake and Derek Hough

Dance: Quickstep to “Guys and Dolls” song

Derek decides the way to get the best results from Ricki is to be tough on her, but that just leads to a lot of bleeping when they get mad. She’s also determined to beat J.R. at the quickstep and regain her spot as the best dancer in the competition.

Donning a gold dress, Ricki does a lot of arm flailing and looks determined to move her feet as fast as she possibly can. Len loved the performance, while Bruno calls it impeccable style with outstanding choreography. Carrie Ann compares it to poetry, which might be going a bit overboard. Over in the Celebriquarium, Brooke notes that Ricki was going after J.R. “He is the guy to beat, he is amazing. ... I’d happily take second to the war hero!” Ricki says smoothly as J.R. comes over to kiss her cheek. Scores: 10, 9, 10 for a total of 29 points.

Activist Chaz Bono and Lacey Schwimmer

Dance: Tango to a “Phantom of the Opera” song

Cher fact alert: She loves “Phantom of the Opera.” Chaz says he’s very familiar with the play because his mom was a fan. That doesn’t help Chaz out with the tango, and an increasingly-frustrated Lacey tells Chaz that he has to step up his skills.

Wearing a “Phantom” mask, Chaz seems to do a good deal of standing around while Lacey twirls, but he gamely tries to keep up at the end. “It was like watching a cute little penguin try to be a bird of prey,” Bruno says, which is his version of a scathing insult. Translation: Chaz lacked intensity in the dance. Carrie Ann agrees with Bruno, but thought that Chaz did show some attitude. Scores 7, 6, 6 for a total of 19 points.

Chaz Bono and Lacey Schwimmer (Adam Taylor/ABC)

Dance: Rumba to a “Rent” song

Hope feels bad that she had a slight meltdown last week, but Maks claims everything is forgiven. However, he calls in reinforcements with three female members of the “DWTS” dance troupe to help teach Hope how to be sexy this week. Maks sits back and lets the women do all the work. But as soon as they leave, Hope regresses back to her old ways, and Maks gets bleeped like crazy as he criticizes Hope’s lack of sexy dance moves.

Hope’s costume involves a pair of shorts, boots and a crocheted sweater, so we assume she’s rebelling against Maks and the judges and their “not feminine enough!” commentary. The rebel move doesn’t work, as Len criticizes the boots and her moves, and says it was their worst dance of the season. Maks doesn’t take this too well, and he and Len start bickering. In the Celebriquarium, Maks is still miffed about being criticized. “This is my show, I helped make it what it is,” he tells Brooke, saying he doesn’t like being judged unfairly. Scores: 7, 6, 7 for a total of 20 points.

Actor J.R. Martinez and Karina Smirnoff

Dance: Quickstep to a “Chicago” song

Karina tells J.R. that their quickstep for this week is the most ambitious one that she’s ever choreographed on “Dancing With the Stars.” She pushes J.R. to try especially challenging moves in rehearsal, even to the point of doing a cartwheel.

J.R. manages a cartwheel on the dance floor, and expertly whirls around with Karina, who, wearing a wig, looks just like Velma Kelly from “Chicago.” Len is a huge fan, and Bruno says J.R. created a “rip-roaring” number, and Carrie Ann is equally ecstatic. The scores prove the excitement. Scores: 10, 9, 10 for a score of 29.

Only seven contestants means there’s still time to kill, so Kristin Chenoweth comes out for a song and dance number. She sings “Maybe This Time” from “Cabaret,” which is also a song she performed on “Glee” last season, and then segues into “I Could Have Danced All Night,” hitting some glass-shattering high notes at the end.

And last but not least, Carson Kressley’s back! But just to serve as “creative director” for the first group dance of the season. With a medley of songs from “Sweet Charity” and “Cabaret,” Carson runs around with a cane while everyone’s learning the dance, and it’s generally chaos as everyone practices lifts together.

Luckily, this does not lead a disaster — no one drops anyone during the actual group performance, which involves everyone dressed in some form of top hats or vests. The judges love the Broadway tribute and give (metaphorical) extra points to Nancy Grace for completing a flip with Tristan and not falling over.

Last week: ‘Dancing With the Stars’: Time for ’80s night

Last week results: ‘Dancing With the Stars’: So long, Carson Kressley

Full coverage: ‘Dancing with the Stars’

GALLERY: Click the image above to view more photos from ‘Dancing with the Stars’ season 13.