The "mental actor" is Charlie Sheen and what he has proven is what Barnam allegedly said "there's a sucker born every minute."
Here's a snippet regarding Sheen's present tour from The HOLLYWOOD REPORTER:
"Tickets for the 6,000-seat Radio City (show) ranged in price from $79.50 to $519. For $750, ardent fans can meet the actor...."
"The one man show has sold out twice at NYC's Radio City...."