HBO says academic Michael Eric Dyson will be filling this week's guest slot, after Senator Al Franken bowed out of "Real Time with Bill Maher." The Senator declined to appear on the show the wake of Maher's use of a racial slur last week. Maher was roundly criticized for using the N-word in a joking reference to himself as a house slave. He later apologized, but Franken called his remark "inappropriate and offensive." Dyson is an African-American author and Georgetown University sociology professor and tweeted a measured defense of Maher.