The day my last ever coursework was due.
This went quite badly wrong. I left it too the last minute (so what’s new) and then completely ran out of time for it, and ended up handing it in very unfinished. It was a program, and only did the very basic stuff.
Oh, and I didn’t quite realise this was a mere 3 days before my first exam – I had assumed I had a week in between, but I should have known that 17 and 20 are only 3 apart.