I saw this on Breitbart first, but I didn't think it was a real video. The YouTube link is in the article.
James O'Keefe videos force Democratic operative's firing, forces another to distance from DNC - Business Insider
"The two videos, released on Monday and Tuesday, appeared to show Democratic operatives discussing how they paid people to incite violence at Republican nominee Donald Trump's rallies, among other claims."
"Foval said in the video that he's paid 'mentally ill' and 'homeless' people to 'do some crazy stuff before.'"
DNC interim chair Donna Brazile: "The discredited source of these videos, James O’Keefe, is a convicted criminal with a history of doctoring video to advance his ideological agenda..."