I too have 4 children, a 16 year old with ADHD, a 10 year old, a 6 year old and a 5 year old.
The 3 youngest share a room. I can remember a time when they would be going to bed the same time as me as I had no routine.
Since bringing in a routine (and being firm with the rules) they now all go up to bed at 7, they get to choose a film to watch in bed (they take turns to pick) and if they play up the tv goes off.
I found it good to set the rules with the children - so they get to help decide the rules & the punishments, they know what they can & can't do & what the punishment will be for breaking the rules. These rules I then printed up and put on their bedroom door.
If they start to play up I call upstairs asking if they want me to turn the tv off, this is now usually enough to calm them again, in the beginning I would call up 3 times then off went the tv. If they continued to play up they would loose thier favourate toys the next day (and so on through the punishments they had chosen when we set the rules).
The hard part is following through with what you say so they learn you mean what you say.
When they have learned you mean what you say they listen so much better.
