One of the participants is Tricia Willoughby, the 14-year-old girl who was booed and heckled by protesters at the Tea Party rally here at the Capitol last April. You see her at 0:21, 4:22 and a few other places.
Here's Blaska's post about today's event:
That was the Blaska Bloggers’ first annual Capitol Rotunda conservative sing-along. Fifty folks off all ages and sizes showed up to sing....There's a picture of Meade and me with Blaska at the link. Meade participated. I observed and too pictures.
At 3:01, a man up on the 1st floor — probably and anti-Walker guy — asks the group to sing "This Land Is Your Land," and there's a bit of a pause, and then they sing "The Marine Hymn." That's an interesting left-wing/right-wing incident!