Here's what you probably won't find this week at the respective Dallas headquarters of the Clinton and Obama campaigns: Smokey rooms, suits, loudly ringing telephones, hordes of volunteers stuffing envelopes, a majority of people over 35.

Here's what you will find at both locations: Squadrons of laptop computers, cellphones, snack food, a steady stream of people expected and unexpected, and a rising sense of urgency.

As early voting in Texas was winding down this week and as the campaigns cranked up their efforts for Tuesday's presidential primary and caucus, we visited both offices to catch the vibe. (The McCain and Huckabee campaigns also have Dallas-area offices, but the race for the GOP presidential nomination race is all-but-over nationally, so the stakes are much higher in the Democratic primary.)

Both headquarters had an air of being hastily thrown together — and for good reason. Neither office has been open more than a couple of weeks. Staffers and volunteers for both campaigns acknowledged that neither organization had figured Texas would be this important until the results of the Feb. 4 Super Tuesday primaries were tallied. While the campaigns had worked many months in states such as Iowa, New Hampshire, California, and New York, they needed to spin up to full speed in Texas in a matter of days.

Here is what we found:

The Obama headquarters, inside the Southside on Lamar building just south of downtown Dallas, is almost impossible to find from the outside. One tiny sign, smaller than a dinner plate, points to the door. The office itself looks like the set for a hip sitcom. The huge main room has no walls and not many tables. Small groups of mostly 20-somethings slouch quietly in front of computer screens, earbuds stuck in their ears. About 30 volunteers and staffers are about equally divided between men and women, and between whites and those of various skin tones. On one recent afternoon, some smaller offices were so short on chairs that volunteers sprawled out on the floors with their laptops, looking like a high-tech slumber party.

It's a relatively quiet place, with much of the activity happening online. Along one high-glass window of the main room is an ornamental dried plant with small red cards tied to it. On each card is a handwritten inscription. One reads: "Our hearts, our souls, the total being of who we are — all for you."

The other tenants on the first floor of the former Sears, Roebuck & Co.'s Catalog Merchandise Center include several art galleries, a computer animation production company, and a coffee shop where the campaign used the WiFi computer connection until their own link was set up.

A long table is covered with mostly-healthy food — fresh fruit. salad, salsa and chips, organic cookies.. A handwritten sign suggests "health and wellness" guidelines for people wanting to donate food. The table is the responsibility of Susan Staples, 53, an American Airlines pilot. She and her daughter had gone to New Mexico before that state's Super Tuesday primary. Then she responded about 10 days ago to an e-mail from the campaign that it was looking for Dallas-area volunteers.

"When I got there, they said they were looking for someone to make sure there was coffee, and the next thing I knew…" her voice trailed off as she pointed at the buffet.

"We have nicknamed this table the Table of Brotherhood," she said.

Richard Klass, 67, is one of the out-of-state visitors this day. The retired Air Force colonel is a volunteer co-chair of the Veterans for Obama Policy Team. He's worked for the campaign since Iowa and has visited New Hampshire, South Carolina, Virginia and Maryland. The Dallas office was a step up from some, he said.

"The one in Iowa, there was probably more tape than carpet," he said.

The Clinton headquarters, tossed into a building near Fair Park, looks more like a traditional campaign office. Campaign signs festoon the outside. Inside, the building has mostly small rooms, packed with chairs and tables, notes pasted on the walls. But there is the large yoga studio at one end of the hall that's still being used for several classes a day when it's not being borrowed by the campaign. And there's a parrot perch in the front lobby with the sign warning that "he bites."

This office is in a mixed neighborhood that includes a couple of auto repair shops, a drilling equipment company, and several old wood-frame houses. On average, the volunteer mix seems a bit older, whiter and more female than the one at the Obama HQ the previous day. But it's still a highly diverse bunch.

The food here is in a kitchen and leans heavily to high-carb: Candy bars, chips, a huge sack of bagels, sodas.

A steady trickle of visitors come through the door. They want yard signs, they want flyers for the Clinton rally scheduled for Saturday, they want to volunteer for whatever needs doing.

Barbara Nelson, "over 50," from New York has just arrived. She's a member of New York Ambassadors for Hillary, a group of volunteers who know the candidate from her Senate campaigns. Not that she had expected to be working in Texas until a couple of weeks ago.

"Things certainly took a different turn than we expected a year ago," she said.

Running the front desk, at the table next to the vacant parrot perch, is Laurel Headley, 49, a lawyer from of Berkeley, Calif. She's been a Clinton supporter for more than a year and just a few days earlier "jumped in an airplane in a moment of inspiration" to come to Dallas.

On the couch in front of her table, Cristina Antelo balanced a cellphone on one ear while peering into her laptop, preparing to talk to a woman waiting for instructions on the next chair. Ms. Antleo, 31, grew up in Cedar Hill and now works as a lawyer in Washington, D.C. As an undergraduate, she had an internship in Ms. Clinton's office. The day after Super Tuesday, she told her boss that she was headed home to Dallas to work in what would obviously be an important campaign. The bilingual Ms. Antlelo is mostly working on Hispanic outreach here.

And after next Tuesday? "I may for to Pennsylvania," site of the next large primary. "I'm actually that jazzed."

How tech-heavy is this campaign office? There's no copy machine. The printers are hooked up to the computers, but the copy machines that would have been the whirring heart of earlier campaigns are absent. (The Obama office has only one copy machine.)

But that doesn't mean this is a paper-free office. In one corner of the yoga studio, Walter Holton, 52, stacks huge piles of fliers for the Saturday rally. Mr. Holton is a lawyer from North Carolina, a former U.S. attorney appointed by President Bill Clinton. Last time he was in Texas working on a presidential campaign, Walter Mondale was running. The Internet has changed the feel of campaigns, he said.

"The 2008 campaigns seem to be a little easier on the feet and a little harder on the rear end," he said.