marathon sessions are the norm for me it seems (be it TV shows/films or games).
If we are talking continuous, it rarely gets over 13 hours online or offline, single or multiplayer. RPGs and the like offline but online it is usual some form of shooting game (some of the big battles take hours and breaking up a good team)
With small breaks for sleep then it gets a bit worse. Good for testing out new machines though.
With friends taking turns it is worse still. GTA on the PS2. Friday we vanish early, next thing I know I am staggering back Sunday night.
With friends and multiplayer (and the occasional bit of sleep - got this one hour sleep thing down) then 60 hours has been known. Heavily modded team based shooters with a few bots and massive maps....... good times.
Usually all done with nothing stronger than chocolate spread (coke (as in cola) keeps me up for hours and stuff like red bull could probably revive me if I was dead).
And just because I can, board games have taken a fair hammering as well.
All this being said I have never decided to pee into a bottle or something (or worse a catheter*) like some people I have seen/known.
*seriously, voluntarily (as in with no medical basis whatsoever) had a catheter inserted so as to play games.