my $now = time;
my @now = localtime $now;
my $start_of_today = $now - $now[0] - 60 * $now[1] - 3600 * $now[2];
my $days_since_monday = ($now[6]+6) % 7;
my $start_of_monday = $start_of_today - 86400 * $days_since_monday;