NEW YORK (AP) — John Mellencamp , Jay Leno and Whitney Cummings will be among the guest speakers when Bill Maher receives the Mark Twain Award for American Humor during a June 28 ceremony at the Kennedy Center. The center disclosed the list Monday in an email sent to members, who were offered packages ranging from $99 for a seat reservation to $1,500 and more for seating and admission to pre- and post-show receptions. The announcement also marks a notable change in how the center is identifying