What's your longest gaming session?

Just this past weekend, I had a 4 hour game session with Resident Evil 5 and most of that time was played on Mercenaries (Duo).

Mass Effect. 13 hours 29 minutes. Well 15 hours 29 minutes if you count the two hour break I took.

Probably about 6 hours

I've pulled a few all-nighters of straight gaming before.  Great times those are.

Final Fantasy XII- 9 hours in a row.

27 hours on Flight Simulator 2004

A little over 36 hours, playing various games.  There were obviously some breaks in there for food and stuff, though.  A group of friends came over one day and we Brawled, Geared, CoD'd, Rock Band'd, and L4D'd.

i would say 5 or 6 hours with cod 4 and waw

Managed a 30 hour marathon Oblivion session a couple of years ago. Bathroom breaks and food included. (my wife was in America at the time and I was off work so I figure what the hey.) Watched an entire season of 24 back to back a few days later. Figured I wasn't going to get away with it any other time :P 

All nighter on Fifa 09, 'twas brilliant

Probably about 5-6 hours playing single player/multiplayer on Jump ultimate Stars (DS)
I believe I have maxed out the timer to 99:59:59 and probably done that about twice over, I wish they would make the game timers on some games go much higher than they do. 100 hours for an awesome game is nowhere near enough.

I've probably done 24 hours somewhere along the lines, my folks used to have to tell me to go to bed from the main computer room (before I had the internet in my room) because I gamed for hours, one night they forgot............

probably the day i got littlebigplanet, at one point i played it around 14 hours strait.....

Persona 3 FES, and that was a solid 10 hours. 

I played Harvey Birdman to completion in one session.

Longest single game session was 8-9 hours of GTA4 when it came but longest ever was my Endurance Run marathon. I some how missed a whopping 60 episodes before I realized what was going on. So one weekend just started to watching those. 60 episodes or good 30 hours of P4 in 48 hours. Next night I had a Persona 4 dream :) 

When Rainbow Six 3: Black Arrow came out, me and an Xbox Live buddy racked up 16 hours right out of the box. I'm glad I have a life these days haha.

while trying to get the 7 day survivor achievement, played like 16 hours, it was crazy. 0_o

I can quite easily start playing at around 7pm and keep playing till 5am. This happens pretty frequently.

Oh, and once I sat down and played MGS Portable Ops to completion (speed run of course).