How do you convince a 4 year old...

How do you convince a 4 year old that it's bedtime even though it's still very light out? Lexie insists that it can't possibly be bedtime since it's still "morning". The sun is setting at 11 p.m. and rising at 4:30 a.m. right now - and it's only going to get later and later as we get closer to June 21st. All of us are having a hard time getting to sleep. I think that I need to invest in some good drapes - the blinds don't seem to be cutting it and are letting in too much light. Plus, we have lots of neighbor kids (and adults) who are taking advantage of the light and riding 4-wheelers and motorcycles up and down the roads. I think it's an Alaskan rule that you have to own some sort of ATV - I wonder how long they'll let us stay here without one :)
Well, it's now 11 p.m. and I'm going to try AGAIN to put Nick to sleep. Maybe he will realize that it's bedtime now. Wish me luck, because I'll need it :)