On what would have been Roger Ebert's 72d birthday, Matt Zoller Seitz, the editor of RogerEbert.com, will host a Google Hangout with scheduled appearances by Ebert's widow, Chaz; Steve James, the director of "Life Itself," the documentary about Ebert's life and work; and special guests including Werner Herzog, John Singleton, Anne Thompson, Alan Polsky, Josh Golden, Kartina Richardson, Ali Arikan and Sam Fragoso. The chat goes live at 2 p.m. Eastern and will be archived for later viewing. You can post questions in advance here.