There has been a get-together all this week out at the Astrodome with a lot of things going on that tell you something about this city:

Saks Fifth Avenue is at the Astrodome offering "the finest Russian sables" for sale in the international visitors' lounge.

An Iran Air booth is "doing good business" in nonstop flights to Tehran from New York.

A quartet is singing, "That's Our Offshore Roughneck, He's Some Guy."

A comedian hidden someplace and speaking through a dummy is telling some dude in double knits, "I can't believe you're wearing white shoes. They went out in '57."

An authority is giving a paper on "the dynamic response of flexible offshore structures to regular waves."

A downhole heave compressor is on display.

So are a lot of women.

And a few of them, like the items in the exhibits, are for sale.

As surely as the State of the Union Message reminds Washington it is the nation's capital, this is the week that reminds Houstonians that they are in the world's energy capital, if they needed any reminder, which is doubtful. After all, Sen. John G. Tower (R-Tex.) once observed to a visitor, "If we had gone independent in 1845, we could be in OPEC now."

So, unable to get Texas into OPEC, they get OPEC into Texas, with things like this week's Offshore Technology Conference. Perhaps 70,000 people from Texas and the rest of the world are pouring through the Astrodome, Astrohall, Astroarena and all of the Astroparking lots to see everything from aircraft to winches (towing) and winches (lifting) anything associated with finding oil or gas offshore, recovering it, transporting it and processing it.

Such is the draw that there was a full page help-wanted ad this week proclaiming the "opportunities in Qatar," and listing the benefits for employes of Qatar's national petroleum company.

This conference, known commonly as the Oh-Tee-Cee, starkly illustrates Houston's role as an international crossroads marketplace for oil technology and expertise. But other things were going here this week that say something else about the nation's fifth largest city.

Move to Houston and the first thing they'll ask you is, "when did you get here?" If the answer lies somewhere between October and May, the next line is, "Then you haven't . . .

". . . suffered a Houston summer. But we are now well past what a local columnist calls Window Day - that one day between Houston's two seasons when you can open a window and not freeze or fry. Temperatures this week have been running above 90, with the humidity frequently at 100 percent.

This has disrupted traffic, because right around evenign rush hour it gets so hot that the freeways are buckling. Not just one, but seemingly every one. Said one drive-time radio announcer the other night, "He's going to be late and grouchy, ladies."

The city and surrounding area added a net of 441 cars a day to the road system last year - and not a single inch of new highway. According to a Texas A&M University professor, that was enough cars to stretch from here to Plano, which is just past Dallas. So, of course, you're late and grouchy every night.

And not that the buckling of the freeways is the only problem with what in many places is an absolutely wretchedly maintained city. The other day a water main burst and created a cavern so big it swallowed an entire full-size automobile. A few days later, a young boy drowned in a pool created by yet another broken water main.

It was also the week that saw this city's Mexican-American community, which makes up about 20 percent of the population, torn by violence. A Sunday night fight in Moody Park, in the predominantly Hispanic area in the city's North Side, escalated into arson, looting, two stabbings and other aggression when police tried to arrest one of the fighters.

Mostly youths were involved, and one leader in the community fears for the summer when school is out and those kids have nothing to do all day. Outside agitators were blamed, and by midweek some people in the Hispanic community - which has been simmering over police brutality against Mexican-Americans for a year - were calling for tougher police measures to stem the disturbances.

Only a handful of people were injured, the number of arrests was relatively low and few stores were destroyed. Still, It was Houston's first real taste of an urban disturbance, and illustrated that in the glare of the glassy oil citadels here, matters of poverty, poor education, discrimination and unemployment exist.

But if the violence illustrated Houston's unaddressed problems and the weather its insoluble ones, it is still the Offshore Technology Conference that reflects what this city is mostly about.

Perhaps the world's largest toy show, the OTC draws sellers and buyers worldwide - Germans exhibiting to Indians, Norwegians to Mexicans, 1,800 companies in all. Some 15,000 hotel reservations have been placed, 8,000 of them for foreigners. Each delegate will spend an average of $323, excluding transportation, about which one airline officials says, "It's like Christmas." Exactly 284 technical papers were prepared for delivery to the few who cared.

The stakes are almost unimaginable. During all of this, Shell Oil's top man for exploration was telling a trade group that of the nation's domestic oil and gas production predicted for 1990, half must come from fields not yet discovered.

Much of that, of course, will have to come from offshore. So you can see why they bring airplanes, helicopters, rescue boats and work boats, blowout preventers, valves, pumps, seismic data, offshore docking mockups, miniature tankers and everything else to the OTC, including a navigation system accurate to within six feet as far as 100 miles from land.

These toys are usually accompanied by models who in many cases fit what has come to be the national expectation of Texas women - the Kilgore Rangers, the Dallas Cowboy cheer-leaders and Farrah Fawcett Majors.

What they do in many cases is just stick emblems on you. "We're ready," reads one sticker being applied by a couple of women in shorts and scanty tops. "you're cute," says another as she sticks a passerby with another emblem. Indeed, there are people who are competing to see who can acquire the most emblems in the most places. There are key rings and screwdrivers, ice cream cones and toy plastic hardhats. And hand-embossed, custom-made hardhats from Indonesia at one booth.

Claudia Sharp, who is giving out keyrings for the Grime Fighters cleaning equipment says, "It's like trick or treat."

Speaking of tricks, it is legendary that the OTC draws prostitutes from afar and from Houston. "These girls follow the conventions," says vice squad Lt. M.C. Simmons.

"They have a circuit that begins in Seattle. They use a pay phone or a house phone or just walk down the [hotel] halls going door to door. I don't know where they go from here."

Or they ply the crowds in the Astro buildings or the hospitality suites. If Jimmy Carter knew what was going to be written off on some expense accounts, it would make the three-martini lunch look legitimate. CAPTION: Picture 1, A Fiberglass model of a "Christmas tree" - a gas wellhead valve - on display at the world's largest toy shop. The real things cost $400,000, the model $30,000, by F. Carter Smith for The Washington Post; Picture 2, A $362,000 Bell helicopter for flying crews to offshore locations is on display.