insomnia :(
I used to do the same, going for long walks to try and tire myself out. It got to the point where lack of sleep had me genuinely spaced out and doing things which in a clear state of mind would have been judged unbearably reckless.
I walked around parks in both North and South London (wherever I was living at the time) after dark, asking strangers for cigarettes and so on. It was very weird.

Fortunately for me I'm a six foot three broad-shouldered young man and the average prospective mugger didn't get close enough to note my lack of muscle tone and soft Oxfordshire upbringing.

Sleep's ace, isn't it?
( Mockingbird Practitioner of SCIENCE, Mon 4 Feb 2008, 9:40, Reply)