3 days when I had to complete documentation for an audit. I only returned to my room to shower and change clothes for the next day. That too I left at 8AM and returned at 09:30AM.
2 days when I had to complete setting up the office network over the weekend. Note that this was over a weekend.

And this is without counting the many hours I've spent semi-working at hackathons. I've gone up to 60 hours without sleep, coding the shit out of my brains.