"Stadiums and arenas don't work alone," says Robert Mankin, a sports specialist with architect NBBJ's Los Angeles office. "They can act as a catalyst."

As Cincinnati learned, a football and baseball stadium aren't busy enough to start the redevelopment process. NFL teams only play seven or eight games at home, while baseball stadiums can host 80 dates or more. Arenas, because they can mix basketball, hockey, amateur sports, rock concerts and family events can be busy more than 200 days a year in a big-city market.

NBBJ designed the 1999 Staples Center arena in downtown Los Angeles, but Mankin says it became much more successful once the Anschutz Entertainment Group's 4-million-sq-ft L.A. Live sports-and-entertainment complex rose around it in the following decade. AEG wants to boost L.A. Live with the 78,000-seat Farmers Field, a football stadium designed by Gensler. It says it will not ask for public money. AEG competes with The Majestic Realty Co.'s NFL stadium proposed 18 miles east. Designed by Populous, it is also self-financed. The project that lands a team can proceed.

San Diego Padres former owner John Moores, partnering with the city's Centre City Development Corporation, built condominiums and a hotel on five parcels in a district of warehouses surrounding the 2004 PETCO Park baseball field (ENR 3/8/04, p. 26), but a planned 3.2-million-sq ft "Ballpark Village" has yet to move ahead. Moores sold his interest in the Padres this year.

Facilities do most for cities when they reinforce redevelopment trends already under way. Fans can dine and drink in Denver's downtown LoDo because the adjacent 1995 Coors Field is not isolated from the redeveloped warehouse district by acres of parking. San Francisco's Caltrans commuter-rail station feeds people to the 12-year-old AT&T Park through the South of Market neighborhood that's boomed since the 1990s. Downtown fans filter through Seattle's historic Pioneer Square to reach a baseball and football stadium that cut dramatic silhouettes on the skyline.

Other cities hoping to kindle such synergies with new facilities have garnered citizen support for public financing. In Minneapolis, teams and owners overcame taxpayer skepticism by agreeing to cover well over half the cost to renovate the 22-year-old Target Center arena and to build a $975-million stadium. The recent collapse of the Metrodome's inflatable roof and the Vikings threat to move added urgency to the effort.

Local governments will lend as much as $145 million to the $537-million Seattle arena project, for a site adjacent to the ballpark and stadium. Much of that cash would be applied to a variety of off-site improvements.

The ugly financial climate does not mean that stadiums and arenas will be built cheaper, because trends in public expectations and technology are likely to add to costs. Cities are asking for memorable designs that draw facilities into the life of the city. That's why Forest City Ratner hired first Frank Gehry and then SHoP Architects to put a good face on the Brooklyn Nets' Barclays Center arena (ENR 7/16 p. 20). SHoP has recently been asked to lead a team that will propose a new major-league soccer stadium for New York City.

Because it wanted to build on a 13-acre pier on San Francisco Bay near the Bay Bridge, The Warriors partnered Snøhetta with AECOM "to add architectural firepower," says Warriors president Rick Welts.

The Oslo-based Snøhetta has never worked on a sports building, but has designed the immensely popular waterfront Oslo Opera House. As much as half the site may be devoted to plazas and gardens, and will be open to the public, even on game days.

With fans addicted to mobile devices or inclined to watch on high-definition home screens, teams are using apps and scoreboard bells and whistles to help fill seats. Designers push harder to optimize sightlines and calibrate acoustics to pump-up crowd excitement.

Owners are saying goodbye to soggy hot dogs sold in smelly, echoing concrete concourses. Along with luxury boxes, fans are finding a variety of clubs and celebrity-chef restaurants linked to premium seats. With pressure to self-finance, teams and facility owners use these amenities to capture even more of the fan's leisure dollar according to AECOM's Stone—but sometimes at the expense of neighborhood businesses.

In searching for the Holy Grail of sports developments, Allentown, Pa., is planning to add new meaning to the word multipurpose venue. The Lehigh Valley Health Network has a strange-bedfellow partnership with the Phantoms hockey team to operate a sports medicine and fitness center as part of an arena complex under construction. Plans call for a seven-story building that will contain 200,000 sq ft of office space.

Time will tell if the mix of sports fans, french fries and fitness makes sense. If it does, the development strategy might become a model for other cities.