On Tue, 17 May 2011 09:15:55 +0100, Mark wrote:

We have a kind of rota and two computers for the 3 kids to share.

We have one computer (for the kids), two kids and "tokens".

Tokens for a fixed period of 30 minutes each.
Maximum of eight tokens per day. (4 hrs)
Tokens only valid between 0630 and 2130 each day.
Home work on the computer uses tokens.
Home work to be done before any computer use.
Tokens do not have to be used.
Unused Tokens give no right to computer use.
Unused Tokens are not carried forward.

If one child is on the computer the other can put a token in "the
queue" and the first *has* to log off when their token exipres.
Mechanical (ie ticking) kitchen timer keeps an eye on the 30 min
periods. Woe betide them if they are on the computer without the
timer running... Tokens can be taken away for bad behaviour and need
to be earnt back.

The system generally works well and was brought with in to reduce
arguments about computer use, make computer use "fair" and limit the
amount of time they spent on the computer. We all sat down together,
talked about it and agreed it, they were 12 and 9 at the time. Two
years on it is still working fairly well.

--
Cheers
Dave.