There is a certain Zen-like state when you're working on a repetitive task. Today, I saw how filthy my trusty old keyboard's keys were and decided to clean them, one by one. As I used a pen to fashion a simple lever mechanism to flick each key off its stand and then rubbed it shiny-clean, the simple repetive nature of my task led my mind to wander and, for the first time in a while, just aimlessly drift from thought to thought. Definitely theraputic. No wonder so many people like cleaning things till they can see their faces in them.