These days, I find a scanned copy someone made (usually hiding
on a Chinese students' university ftp site), bring it over to my
phone, and have it read to me while I lay in bed. (there's a
nice PDF reading app I have on my iphone) I challenge myself by
making the speed as fast as possible. Helps a little. Once or
twice I made a major production out of it. I had the computer
read it to me in a Russian accent (for fun), and had the words
appear on the screen like a teleprompter, scrolling by, with
some interesting music in the background. I think engaging more
of my senses made it easier to focus. But generally, when I
read, I speed read / scan, look for what I need, and close it.