Thirded; I'm curious about that too.

As to brainless activity, cleaning tasks are my favorite. Stupid, picky, clean the shit out of EVERYTHING cleaning tasks. Polishing the silver. Dusting the ceiling. Organizing the socks. Toothbrush-scrubbing the corners. I was lucky enough to stumble on that my first adaptation, and for every one since, or even when I just miss sleep and know I'm going to have a tired night, I make a big list of picky cleaning tasks and just plow through them while I'm tired. They're physical enough to stay awake for, repetitive/stupid enough to not think during, AND they make you feel really great about how you spent the time afterwards!