Most hours of work at once?
A coworker and I did an allnighter because our boss gave us a tight fucking deadline (luckily that almost never happens).
We started normal work at 06:30 and were finisted at 09:30 the next day. Summed up break time: 1h 15m.
I remember that my coworker went home after that but fell asleep in the train and woke up 2 hours later half across the country. Poor soul.
When he left, my boss just arrived in the office and I had to stay 2 hours longer to fix bugs we implemented during our caffeine overdose...

It later turned out that the whole mess was useless, because the client put the project on hold. That was about 8 months ago, or 12, I don't even remember.