NEW ORLEANS — It’s difficult to nail down the last time this antique city was considered cutting edge.

Was it the 1850s, when a coffeehouse owner created the Sazerac cocktail? Or perhaps the 1940s, when a teenager named J.M. Lapeyre invented the automatic shrimp peeler?

Whatever the answer, New Orleans was not defined by its spirit of innovation in the decades preceding Hurricane Katrina. But the flood that changed everything two years ago has changed that too: Today, by accident and by necessity, this city is awash in ideas: the new and the ambitious, the au courant and avant-garde, the idealistic and the slightly nutty.

The New Orleans public education system, long considered one of most ineffective in the nation, has been revitalized with a grand experiment in charter schools; more than half of the city’s public campuses are charters, the highest percentage of any major metropolis.

The city housing authority hopes to transform the shuttered St. Bernard Projects, once one of its most notoriously violent properties, into something akin to a public-housing country club with two 18-hole championship golf courses and a 45,000-square-foot YMCA.

Environmental groups have swept into New Orleans, preaching a gospel of green building, solar power and other ideas familiar in Santa Cruz or Santa Monica but rather exotic here. […]