kchildlock restricts the time a children spends on the PC. Limits can be specified per day of the week, by lower and upper hour limits, max daily usage time, and max weekly usage time. Restriction limits can be applied to applications. Linux/ KDE4.
I use this program in the netbook of my daughter. A very important tool for responsible parents :)
Clearly, this is such a tool that educators and parents love but seems totally ludicrous to most computer-geeks without kids :-)
How long will the kids need to brake it? :)