It will take Vai Vai's 3,500 performers and six floats 70 minutes to parade down the avenue, a grand opera on the move. Our theme this year is "The Way of Light, the Universal Peace." Our section, or block—one of Vai Vai's 28 blocks—has the sub-theme of spiritualism, which is fitting, because our carnival headquarters is a local spiritual center.

I say "our" with the gusto of a novice. A handful of staffers from National Geographic in Washington and London are participating in our first Carnival with the team from the National Geographic Channel in Brazil and Portugal. Icarai Darios, head of marketing, is the volunteer director of two of Vai Vai's blocks. He's arranged for us to join the adventure.

Feathers and Glitter Goo

On cold, dreary days in February, we ordered our costumes. The complete costume, including shoes, costs U.S. $140. Our colors are white and silver, put together in leggings, sleeves, glittering apron and medieval crown. Men wear long white pants. Women wear long white pants, plus sleeveless white tank tops or white bras.

The Carnival girls of your imagination, the ones in the "dental floss" skimpies are on the stupendous floats. We're the ground troops in this half-million dollar performance.

About 10 p.m. on Saturday night, we gear up at a private club near the Sambadome. We rub glitter goo all over our faces and hair and pose for pictures. The gringos are getting nervous. We're singing a song we don't know, in a language we don't speak, and we're being judged!

" Vai Vai, luminosidade!" (Vai Vai is light) we shout with the others. A big television monitor is tuned to a live broadcast of the samba school that is performing in the Sambadome now. Our competition. We drink water. We drink caipirinha (limeaide rum). We drink more water.

At midnight, we pack into buses to head for the Sambadome. We sing "Vai Vai" and pound the roof of the bus like drums.

There we're handed the crowing glory: our feather head ornaments. Artificial ostrich plumes rise five feet above sequined shoulder frames with a train of white net streamers.

Think Follies, think Barbie, think heaven and angels.

Ropes hold the ornament tight to our bodies. We mill around. The group ahead of us lost power on one of its floats. We're delayed by an hour. Vendors hawk beer.

"I need another one," said Australian Kevin Darcy. "I'll get through this my way," he jokes nervously. "I'm doing the Beatles. 'Twist and Shout.'"

A ton of feathers starts to feel heavy.

Icarai and other men and women in white suits wearing disciplina ribbons organize us into lines. We gringos are tucked away in the middle. So is a drunk. A female disciplina chastens a man at the end of my row who is spinning and prancing. Our orders are simple: Always move forward, first to one side, then the other. Fill in the gaps. And above all, BE HAPPY. We're judged on the level of joyous enthusiasm.

Stage fright tightens my chest. The others practiced a couple of nights ago, but I didn't arrive until this morning. I grin at Kevin. He grins back. Twist and Shout.

Show Time

We move forward. Now we can hear the music, blasting from mega-speakers the length of the stadium. Vai Vai, luminosidade! We catch the beat, we shake it up baby, show time!

The fans go wild. I discover this is easy. This is fun, this is ecstasy. "Bah-bah-bah," I sing when I don't know the words. I laugh, I smile, I dance sideways and sing back to a cute young man on my left. Kevin has slipped into the groove. I look back at Orlando Vallone, general manager of National Geographic Channel-Brazil and Portugal, and give a big, double Brazilian thumbs up. This is his first Carnival performance too.

Later we hear that on television we looked like a cloud in a river of color. We hear Vai Vai was the most impressive of the São Paulo contestants. We know that it is bad politics for one group to win every year . . . is this the year we lose? Winners will be announced Wednesday.

But we already tasted victory. A group of behind-the-scenes staffers spent 20 glorious minutes in the spotlight, feeling like the champions of the world. It was heaven.

Cathy Healy is the editor of National Geographic's Intranet website, The Insider. At 7 and 10 p.m. this week, National Geographic Today will be broadcasting live from New Orleans' Mardi Gras celebration.