McEnroe versus Borg. Nadal versus Federer. These are some of the greatest tennis matches of all time. But what if Andy Samberg were to take on Jon Snow, the Bastard of Winterfell, for seven days straight? HBO is exploring that ridiculous possibility in its new mockumentary 7 Days in Hell. Samberg and Harington play Aaron Williams and Charles Poole, respectively, two tennis legends locked in what might be the greatest fake tennis match the world has never actually seen. 7 Days in Hell premieres on July 11th.