One of the best things about summer in New York City is the music. Blonde Redhead (pictured) are just one of the many acts playing free concerts in the city in the coming months. We preview don't-miss concerts, including festivals like River to River, Celebrate Brooklyn, and Central Park's SummerStage series. And, Maura Johnston of the music blog Idolator joins us with a top-10 list of free summer concerts.