I close my eyes, take slow deep breaths, and with each breath slowly count up and down from 0 with the high number increasing by one on each cycle. Eg. 0 1 0 1 2 1 0 1 2 3 2 1 0 1 2 3 4 3 2 1 0… It requires just enough concentration to keep my brain from drifting off to other thoughts (usually), but is boring enough that I rarely get to 9 without falling asleep. If find my mind does wander, I just try again.
I will, however, absolutely condem anyone that posts that much text center justified.