Star Lord (and a few other characters) has the ability to make people dance. Hold B and he will bring out his radio and anyone nearby will dance. You can do this any time you are outside in the Chronopolis area. It's best done on a spot where a lot of people walk by. You have to have five people in the same spot dancing. If you can find a spot with two or three just stand there with your music going until more walk into the area and they will dance too. Sometimes the music will stop if you let go of B.