What time is the ulltimate hour to put children to bed, does it vary with age?

I really got caught up in this one and I wanted it to go on and on. I couldn't get to sleep last night all twitchy and stuff going through my head. I will sleep better tonight - I insist! I'll read this again before I go and I'll say pu to the skunk but smile when you get carried down the creek - the water is warm and the ride was gentle!