#!/usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

use XML::Twig;

my $twig = 'XML::Twig'->new;
$twig->parsefile(shift);

my $root = $twig->root;
for my $header($root->descendants('h3')) {
    my $date = $header->text;
    my @events = $header->next_siblings(sub {
        my ($elt) = @_;
        'div' eq $elt->name && $elt->prev_sibling('h3') == $header
    });
    say join "\t", $date, map $_->text, $_->children for @events;
}