The serpentine fitness track at BREC’s Highland Road Community Park was a mass of colorful, moving humanity, as more than 3,000 people of all ages participated in the St. Jude “Give Thanks Walk” on Saturday morning. The event, one of more than 60 held around the nation Saturday to benefit the St. Jude Children’s Research Hospital, in Memphis, Tennessee, was more than twice as large as last year, according to event organizers, who say it will raise more than twice as much money.