Yep we definately have arsenic hour over here, it usually starts by about 5pm... Aidyn just gets so tired, cranky and irrational. He will often refuse his dinner and protest against his shower, and just throw tantrums the whole time...
But funnily enough when bedtime comes around he adopts a whole new attitude and runs around playing happily, pretending that he's 'just too busy' to possibly go to bed! (its very funny!)