The Thanksgiving TROPO opening of 1986 was such a "whiteout" or "blizzard" of DX, that I entirely lost track of how long I was up before finally going to bed, DX'ing all the while (with only bathroom and eating breaks). I may have DX'ed for 26 hours straight, it may have been 47 hours straight...I just don't know.

I suspect that, for many who were "there" for that opening, that opening holds their all-time records for length of ONE continuous DX session.