We have a window in our bedroom which is really loved by the kitticats. Every weekend they woke us up by hanging in the curtain in the hope they could sit by the window. So we came up with a solution in the hope the girls let us sleep just a little bit longer than 05.30 am in the weekend. It worked but it wasn't a pretty solution.
So we made this, it's not quite finished but I think you get the idea.