Jouke Visser is a member of Amsterdam.pm (the Amsterdam Perlmongers) and can be found on Perlmonks almost every day under the username Jouke (how creative :) ).
He has been using Perl since 1997 and rates himself "Perl Adept" according to Nathan Torkinton's Seven Stages of a Perl Programmer.
He writes free software for disabled children, and is currently employed at 2organize.