my @s1_events = 
map { $_->[0] } 
sort { $a->[1] <=> $b->[1] } 
map {[$_, $_->{month}]} 
@$events;

##</code><code>##

for my $ev (@s1_events) {
    my @sd = map {"\t$_->{date} $_->{name}\n"} 
             sort {$a->{date} <=> $b->{date}} @{$ev->{list}};
    print "$ev->{name}\n@sd\n";
}