Save it con your .xchat2 dir as .pl file ( joke.pl for example ) and restart xchat, then, for usage, do /joke message :) have fun !

#!/usr/local/bin/perl


# Configure what to say !
$joke_command = "joke";


IRC::register ("Xmms Joke Plugin ", "0.1", "", "");
IRC::print ("Usage /joke <joke>");
IRC::add_command_handler("$joke_command", "print_joke");

sub print_joke
{
my $joke = shift;
IRC::command("<joke> $joke </joke>");
}