Sleepless in Colorado

I thought I had learnt my lesson of travelling west to the americas before, but although I applied what I thought would work, I still can't sleep. Mind you, when I was last here I was 20 and fit! Now I'm 25 and decidedly unfit, I find myself waking at 4 or 5 in the morning with nothing to do but use the 24 hour gym or surf the net.