Comedian and media mogul Byron Allen. (Photo courtesy Byron Allen Media)Paramount’s CBS will air a special two-hour presentation of “Comics Unleashed” that celebrates the late night program’s 20th anniversary, the network announced on Wednesday. Comics Unleashed debuted in first-run syndication on local television stations in 2006. The show is known for its four-quadrant comedy — no politics, no roasting — that is intended to generate mass appeal among TV viewers disenfranchised by the polarized late night landscape. By comparison, other late night fare on NBC and ABC have retention rates between 78 percent and 88 percent, the data shows.