Filling a rota fairly

Giganews Newsgroups
Subject: Filling a rota fairly
Posted by:  Brian Clarke (bxxcfi…
Date: Thu, 03 Jul 2008

There are 5 staff members who want to park their cars at the office, but
  only 3 parking spaces. So the spaces need to be allocated by rotation.

I looked at the past rotas, and they don't seem to have been fair. It
would be good to do the allocation automatically, perhaps in Excel. If
we use cols D-F for the parking spaces and a row for each week, is there
a general method which will quickly fill in the rota?

I know that this is a relatively trivial task to do manually, but it's a
type of problem I haven't come across before, and it's interesting. I
suspect the MOD function might be useful here, but I can't put the thing