Time limited internet connection

[Kiraly Zoltan <yo2lux_(_at_)_openbsd_(_dot_)_wplink_(_dot_)_net>]

I want to build a home network using OpenBSD as gateway. A child in 
network have a computer, and like to surf the Internet. I want to drop 
her Internet connection at night (11:00AM) because the child don't go to 
sleep.

I don't want to unplug the network cable, i need to do this job with 
OpenBSD.

Exist a proxy server or solution which limit the Internet connection 
using time? An example: Drop internet connection at 11:AM night and 
allow Internet at 6:00 AM morning.

Thank you very much