It is going on right now. In the fifth set and it is 53-53. They have been playing for more than 8 hours. :D
http://uk.eurosport.yahoo.com/tennis/livematch/380703.html

59-59, game isnt over yet :D its gonna continue tomorrow and the winner already has to play his next round game tomorrow, how the hell is he gonna be fit for that match :D

Yup. I think they will postpone their next match for another day. I think this is the second time the match is postponed. I think it started yesterday. :D

Yeah it did, heard they were just acing each other :D They needed to be 2 points apart but sounds very strange that one couldnt atleast score 2 or 3 in a row.

...At the 2010 Wimbledon Championships John Isner (left) defeated Nicolas Mahut (right) 6-4, 3-6, 6-7(7), 7-6(3), 70-68 in the world's longest tennis match. The match lasted 11 hours, 5 minutes.