A quick little note about turning off the internet at a certain time.  If you can assign all your kids devices IP addresses in a certain range, then you can easily cut them off the network at a given time with an addition to the shorewall rules file

DROP dmz:192.168.12.151-192.168.12.199 net – – – – – – – – timestart=22:00&timestop=23:59&weekdays=Sun,Mon,Tue,Wed,Thu&localtz
DROP dmz:192.168.12.151-192.168.12.199 net – – – – – – – – timestart=00:30&timestop=02:00&weekdays=Fri,Sat&localtz

As you can see, a certain address range on my dmz gets dropped at 10pm on school nights and 1230am on weekends.  Hope someone finds this usefull