IDEAS CITY, a biennial festival, brought more than 50,000 people to the Bowery for each of its past two runs. Did those people leave the festival enlightened? We can’t know for sure, but we can say that, at the very least, it got lots of people thinking about the roles they play as urban residents in New York and beyond. The festival consists of talks, performances, screenings, art exhibits, and other activities that take place over a three-day period. Each event tackles the subjects of art, civic life, politics, the environment, technology, or architecture — or some interdisciplinary combination of these. For example, at “Wasted Food x Wasted Space” on Friday morning, conferences about waste management take place over a breakfast of “rescued” food in a garden pavilion made entirely of garbage. The entire festival is the brainchild of the New Museum, so you know you are in good hands.