Vornado has 7.3 million square feet of offices in Crystal City, Va. CoStar Group

Martin Ringlein recently moved his business to Crystal City in Washington's Virginia suburbs, but that is about all he has in common with the defense agencies and government contractors that for years dominated this area of boxy, low-slung office buildings.

A founder of nvite Inc., a one-year-old event and ticketing social-media company, Mr. Ringlein likes to kick back in his office and play Mario Kart in front of an 80-inch flat screen television. On many afternoons, he and his colleagues hop in an elevator and play basketball on a new court outside.

"Nobody else around here plays basketball, so we kind of own it," Mr. Ringlein said. "There's still a lot of suits and ties walking around."

Mr. Ringlein and his five co-workers represent both the opportunity and challenge before landlord Vornado Realty Trust, which is embarking on a grand experiment to create a cluster of technology companies amid its 7.3 million square feet of Crystal City offices. It was just 82% occupied as of the first quarter.

Tech clusters have popped up in numerous cities throughout the country but mostly in areas with older buildings and proximity to hip residential neighborhoods.

That isn't Crystal City, whose collection of two dozen or so modern buildings offer little in the way of architectural distinction or proximity to downtown amenities. Rather their appeal up until now is that they are three subway stops from Washington, two from the Pentagon and one from Reagan National Airport.

Turning Crystal City into a successful tech hub is "going to take a lot of work," said Alexander Goldfarb, an analyst at Sandler O'Neil + Partners. "They're outside of the District and they're in an area that historically, most people have never even considered."

Vornado, Crystal City's biggest landlord, is taking on the challenge because the area's traditional tenant base is on the wane. Federal defense cutbacks over the past decade have caused the area's vacancy rate to rise.

In all, Vornado has about 900,000 square feet of Crystal City space that was vacated as a result of the cutbacks. The company is in the process of redeveloping or leasing nearly 400,000 square feet of that, according to Vornado securities filings.

A Vornado spokesman declined to comment.

But so far, the company has had some success in luring some well-known anchor tenants, often by offering lease terms that analysts consider favorable. Those include the Crystal Tech Fund, a venture-capital firm run by financier Paul Singh that hosts many of the companies it funds in its offices, and Techshop Inc., where individuals and small companies can use machines and tools to help build new products.

Vornado also has struck a deal with collective-workspace company WeWork to open both office space and dormlike apartments to be built in a Vornado office building. It has made small investments to create a youthful vibe with Adirondack chairs, basketball courts and beach volleyball. Food trucks now come on Thursdays, and workers eat lunch at new picnic tables.

"We see enormous potential for Crystal City to become a new hub for the tech and creative community," Mitchell Schear, who heads Vornado's Washington division, said on an earnings call in May. "These smart millennials are in high demand by employers and infuse fresh energy into neighborhoods."

Some real-estate owners have made huge profits off emerging tech centers. In San Francisco, Shorenstein Properties and Hudson Pacific Properties Inc. both have turned around old buildings on the city's central Market Street, including Shorenstein's 1355 Market St., an Art Deco former furniture mart that now is Twitter Inc.'s headquarters.

Meanwhile, SL Green Realty Corp., New York's biggest office-building landlord, has been a winner in Midtown South. For example, in 2012 it bought a pair of old brick buildings in Midtown South in Manhattan that it renovated and then rented to multiple tech companies at rents more often paid by financial firms.

Vornado's challenge is to do this with a neighborhood that feels something like a suburban office park—although street life has begun to pick up. That is no easy task considering Crystal City is competing with growing areas considered more hip, like Washington's Shaw neighborhood.

Adding to the difficulty is that the Washington technology sector is considered relatively small, particularly compared with cities like New York or San Francisco. That gives Vornado a limited pool from which to draw.

Of course, it wouldn't take many small companies to hit it big to fill up much of Vornado's empty space.

"Some of them might fail, no doubt, but the ones that win, they grow fast," said Mr. Singh, of the Crystal Tech Fund, who struck his deal with Vornado earlier this year. Then when companies need more space, he said, it would be natural for them to look at other space in Crystal City. "That's the big bet, from Vornado's angle."

Write to Eliot Brown at eliot.brown@wsj.com