This can be pretty challenging for me. When I have trouble sleeping, it's because I can't find those gaps -- it's like my mind is running on hyper-speed and won't pause. I try to find those pauses in various ways. During the day, simply breaking up my routine can do it. Certainly reading a book will do it -- I don't think while I read, I just take in. That's probably why I often come up with writing ideas when I'm reading ;) TV doesn't work, however -- it's not engaging enough, perhaps.
When I'm trying to sleep, however, a movie is perfect -- especially if it's one I've seen numerous times before. I listen (which stops the thoughts), but I'm not so involved that I have to know what happens next.
It's an interesting exercise -- how do you create those gaps?