If you’re the kind of person who gets excited reading about green roofs and community building projects, Washington Parks & People may be able to fuel your desire to put a hand in making your neighborhood a better place to live. This 18 year-old community group has played a vital role in turning D.C. parks, like Meridian Hill and Marvin Gaye Parks, from dangerous, crime-ridden areas to places where people play and see performances and…