When I walk, and I mean directionless rambling rather than walking to the bookstore, a strange thing happens to time. I will be going and going and going and I will cover so much ground and then I can look at the time and only like 15 minutes has elapsed. Now, I know in my head that I just walked a least an hour's worth. It is like that because I think when I walk and when I think, I get through an hour in 15 minutes easy. No sweat.
And then when I read, the opposite happens. I will sweat over some story, say by Herodotus or Dashiell Hammett, for what feels like no time and then I will look down and it will be bedtime. It takes me 15 minutes to get through an hour, and this, I'm pretty sure is because I am not thinking so much when I read; suppose I'm relying on someone else to tell me their thoughts, and the difference between thinking and telling is a strange one.
Anyway, this is no great revelation to any of you, I am sure, but if you haven't thought about it too hard, it can be a useful trick if you are attempting to manipulate time by either slowing it down or speeding it up. Of course you could just take drugs and space out, but like a great change-up in baseball, you can't just throw that same pitch everytime, no matter how wicked it is.