SUNDAY NIGHT is the last of the Weekend's Weekends free summer concerts (sponsored by the Weekend section of The Washington Post) at the Carter Barron Amphitheatre. It's "Latin Nite," featuring three area bands beginning at 7:30 p.m. with Jaleo, a group that fuses rock and Latin rhythms, followed by the Brazilian flavored Origem, then the Afro-Cuban "Latin Jazz" of Nuevo Cache. Come on down and shake it in the aisles.

We hope you've had a chance to come out to one of our shows this summer. They've been a blast. Carter Barron is one of Washington's unsung jewels and one of the area's best places to see a concert, so don't miss this chance. Free tickets will be available at the Carter Barron box office starting at noon Sunday. The amphitheater entrance is on Colorado Avenue NW just west of 16th Street. For more information call 202/334-4748.

Here's a look at one of Sunday's performers:

ORIGEM'S ORIGINS

When drummer Leonardo Lucini came to this country from Brazil in 1991, he was following the path of his brother Alejandro, who had arrived in Washington the year before. Alejandro, a bassist and one year younger than Leonardo, had come to study music at Howard University and found Washington to his liking. To all of our benefit, he convinced Leonardo to come study at Howard as well. "We played together all the time in Brazil, since we first began playing music, Alejandro on bass and me on drums," Leonardo says. "When I came here, it was our plan to keep playing together, to put a band together."

The band they created in 1993, Origem, found immediate success in the area, playing everywhere from small clubs to huge functions at embassies and places like the National Building Museum. Its blend of Brazilian pop, serious jazz, funk and salsa caught people's ears, "but what's more fun, in a way, is the attention we get from other musicians," Leonardo says. "They hear these different rhythms and they try to learn them. They want to be part of it, part of this growing interest in Latin jazz."

The Lucini brothers are the nexus of a growing Latin jazz scene in Washington, each playing in several different bands, spreading the rhythmic gospel of their homeland. Leonardo lists the elaborate Brazilian rhythms -- baiao, samba, maracatu -- as the foundation of their music, but says that on Origem's brand new CD, "Ijexa," they've been able to incorporate Afro-Cuban styles, along with American musical idioms.

The brothers were well-known in their native Brazil, playing with several major acts, and in constant demand as a rhythm section. "Oh sure, we were the dream of every guitarist down there who wanted to put a band together," says Leonardo, laughing. "One phone call and they got a drummer, a bass player and a place to rehearse."

Playing with his brother is a special treat, Leonardo says, "because we definitely read each others' minds. We've been playing together for more than 20 years now. I hear something he does, and I respond, we look up at each other and laugh." There's even more of that going on these days when Origem plays because younger brother Bruno, a percussionist, has just arrived from Brazil for a visit and has been sitting in with the band. "With Bruno here it's even better. He starts playing something to tease Alejandro. Alejandro plays something back. I jump in to tease them. The other members of the group hear that and see that we all start communicating together in a better way, having a lot of fun. That's the main thing in our music."

While there are two original compositions on the new CD (one by Leonardo, one by Alejandro), it's Leonardo's arrangements of standards like "On Green Dolphin Street" and "Stolen Moments" that most clearly stake out Origem's artistic territory. "We rearrange things pretty drastically," Leonardo says. "Sometimes you can't even recognize the original song. We try to find ways to express ourselves, and you can't do that by sticking to someone else's version of a song."

Joining the three Lucini brothers on stage Sunday are singer Patrick de Santos, keyboard player Dan Reynolds and saxophonist Peter Fraize. Other members in Origem's fluid band lineup include the singer Kiko, piano players Didier Prossaird and Eli Staples and percussionist/singer Alfredo Mojica Jr. Origem plays every Sunday (except this week) and Tuesday night at Chi Cha Lounge, 1624 U Street NW (202/234-8400).

To hear a free Sound Bite from Origem, call Post-Haste at 202/334-9000 and press 8110. (Prince William residents, call 690-4110.)

KIDS DUKE IT OUT

If you need yet another reason to discover the shaded beauty of Carter Barron, stop by on Friday and Saturday for "The Duke's Era Revue," a jazz musical performed by nearly 100 area kids, ages 13 to 21. It's the brainchild of Gloria Hightower, who wrote the script to the musical tying together songs by Duke Ellington and others of his generation.

Hightower is also the president of the Friends of Carter Barron Foundation of the Performing Arts that works with several summer youth programs in Washington. "The youth this summer are just incredible," Hightower gushes. "They're mostly from the Summer Works Program and the Summer Youth Initiative Program. It's been a lot of hard work for these kids who had no idea that musical theater could be so difficult."

She brought in professionals in the field to volunteer with the kids so they could get hands-on experience in lighting, sound, costume, set design, makeup, costumes and especially musical training. "The youth are playing all the music and singing all the songs," Hightower says. "It's so inspiring to see these young people appreciating their musical heritage."

Her script, she says, "ties the songs together, at first telling the history of jazz and Ellington's contributions to the music through narration and through dramatic scenes. Then it celebrates Duke Ellington's 100th birthday. Then it pays tribute to many other great jazz vocalists and instrumentalists: Louis Armstrong, Ella Fitzgerald, Sarah Vaughn, Betty Carter, Cab Calloway."

The 7:30 concert costs $5, and tickets can be purchased (with a 50 cent surcharge) through Ticketmaster (202/432-7328).

A DOUBLE TAKE

Quake II is one of the most popular video games out there, with more than a million copies of its PC version sold over the past year and a half. Its Mac version was released this month, and my gamer consultant Tom Ham has pointed out the uncanny resemblance between Quake II's logo and the graphic for Nation, the nightclub at 1015 Half Street SE. Check it out. Quake II's "double spikes through crescent" seems mighty similar to Nation's "double needles through crescent" unveiled earlier this year.

So is the design team at Nation loaded with gamers who love Quake II's "full-blown action adventure with endless battles and invigorating deathmatches [sic]"? That's how Quake's creators, Activision, describe their game. Maybe Nation's designers feel the nightclub business -- going toe-to-toe with foes such as I.M.P. Productions and Fox 5 -- should be approached like the video game: "Annihilate evil enemies . . . maneuver into strategic attack locations and relentlessly hunt players down . . . suck the life out of hapless victims."

TALK OF THE TOWN

Log on and join a live Nightwatch discussion Friday from 3 to 4 p.m. Put your two cents in on the state of local nightlife and let other people jump all over you! Go to www.washingtonpost.com, click on the "Music" icon, and look for "Nightwatch Live."