This is usually the kicker for me when identifying when I’m entering into mania. 

It starts out as me not being able to fall asleep, so I’ll toss for hours. 
Then, I hear the channels being changed in the living room from MTV, to The Price Is Right, to an Oxiclean infomercial, to The Flinstones, to ESPN.
They switch channels about every 15 seconds and are loud enough for me to make out most of the words.

The first few times this happened, I would almost shit myself, being that I lived alone lol