How long have you played a game in one go?

[Peter_20]

With taking periodic five-minute hygenine breaks and food, but still generally at the desk or playing, near 72 hours.

Damn, ever heard of Guinness' World Records?
Get a place there!

[Nominus Experse]

In one continuous sitting, around 10 or so hours.

[Captain Maxx Power]

Approximately twenty hour session on D2 back in the day. I seriously don't do all-nighters on games anymore, it just isn't worth it. I swear I've had worse hangovers playing games all night than drinking.

[10-Breaker]

My record is 29 hours. After that I felt like I could sleep for 3 days...

[Dreddz]

Im pretty sure I stretched something like 12 hours doing side quests on FFX.