If you've been to church lately, you probably know how unusual it is to see a critical mass of young people in attendance. According to studies by the Barna Group, church engagement falls by as much as 43% between the ages of 18 and 29. Which is why the scene on a recent night in uptown Charlotte, N.C., was so remarkable.

Young people were streaming into a beautifully adorned United Methodist Church, and by the time the lights dimmed for the Christian rock band Gungor (and their opening act, The Brilliance), the capacity crowd numbered more than 600. The audience was not, by and large, made up of members of United Methodist.