For me it was a random 15 minute 1 on 1 with the director that appeared out of nowhere on my calendar.
I checked his calendar in outlook and saw like 8-10 15 minute meetings scheduled back to back. I immediately knew something was up. 5 minutes later my coworker called me almost sobbing saying he had been cut. I knew the deal. 15 minutes later another coworker called and said he had been cut too. Sure enough, my time came too.
It sucked but, I found another job before my last day and managed to pocket the 6 weeks of severance.
Haha, I had actually been wanting to leave, but I had a feeling that a layoff might happen and I wanted that severance. So, I spent all my spare time interview prepping and waiting. Sure enough, we were laid off and I was primed to interview immediately.