Most unrealistic deadline I've had?

The client gives us a project with A 3-month deadline. All good, at first.

3 days later they told us that they're cutting out the funding and they gave us two options: Either stop the project right away and get paid for the work so far, or somehow finish the project in 7 days and get paid for the 10 days worth of work.

My idiot boss chose the second.

Saturdays and Sundays were declared working days, everyone screaming at each other, devs running around scrambling code to make the webpage render and keep it responsive.

Forget unit or automation testing, we only did not null and undefined testing and submitted the project.

Yeah, I hauled my ass out of the company just after that.