How about a competition to find the longest (and most useful) regex
which is a palindrome. (i.e. same read backwards as forwards).
e.g. (stupid example)
s/abc/cba/s
It would be easy to submit, the winner would be chosen by the
members of the monastry voting for their favourites. Entries would be
visible to everyone. Hopefully early entries would get the creative juices
flowing in others.