"Mad Men" star makes behind-the-camera debut with "God's Pocket"
John Slattery, David Cross and William H. Macy form another triumvirate of names at the fest meant for the 'little guy'
The previously announced two-hour special will kick off the new network's first night of primetime programming
John Slattery will appear in multiple episodes of the revived cult favorite
Says of the show's version of the '60s: "If you think that's paradise, you must have a better prescription than I do."