eXaminator generates multiple choice exams in LaTeX quality.
All you have to do is to maintain a collection of questions
in a simple plain text format.
Finally specify how many questions should be taken from each
collection file.
eXaminator will choose by random and maintains a history
(in a hidden file in the local directory) to guarantee that
questions are reused as seldom as possible.

A quick howto can be found at
http://www.perihel.at/examinator/examinator-howto.html