Economic impact of major sports events
While the stadium is in Glendale ("Albatross of Debt Weighs on Super Bowl City," New York Times), most of the pre-game events are in Phoenix, although there are also events in Scottsdale.
The same thing happened with last year's Super Bowl, where the main non-game events were in Manhattan, while the game was actually played in New Jersey. Because most of the pregame action, and rented hotel rooms were in Manhattan, the benefit for New Jersey businesses were limited ("At Super Bowl, New York and New Jersey Will Be Top Rivals," New York Times).
Despite the efforts of local independent businesses to participate (e.g., "Phoenix hopes to score with its super food scene," AP), attendees for sporting events such as the Super Bowl tend to not be very interested in consuming anything local that is unrelated to the game. So the spillover benefits are pretty limited.
That was proved by the last Super Bowl in Phoenix in 2008. Local First Arizona produced a booklet promoting local businesses and districts ("Super Bowl visitors encouraged to spend at local businesses," Phoenix Business Journal). While they have stuff online this year, I noticed they don't seem to have produced a booklet.
The likely sales and ticket admissions taxes reaped by Glendale from the game and related activities will be exceeded by their costs to provide police and emergency services to support the game.
International Handbook on the Economics of Mega Sporting Events is pretty definitive, and discounts the economic claims made by event boosters.
DC didn't get picked for the Olympics, but this book, Planning Olympic Legacies: Transport Dreams and Urban Realities, looks pretty interesting.