<?php

$boards = array(
    "/b/" => array(
        "name" => "Бред",
        "threads" => array(
            "first-thread" => "Webm-тред",
            "second-thread" => "Тред няшных котиков"
        )
    ),
    "/tv/" => array(
        "name" => "Сериалы",
        "threads" => array(
            "first-thread" => "Доктор Кто",
            "second-thread" => "Шерлок Холмс",
            "third-thread" => "Игра престолов"
        )
    ),
    "/pr/" => array(
        "name" => "Программирование",
        "threads" => array(
            "first-thread" => "Клуб изучающих PHP",
            "second-thread" => "JavaScript тред",
            "whoops" => "C++ тред"
        )
    ),
    "/mov/" => array(
        "name" => "Фильмы",
        "threads" => array(
            "pinned thread" => "Поиск кино",
            "first-thread" => "Драйв",
            "second-thread" => "Мертвец Джима Джармуша"
        )
    )
);

foreach ($boards as $key => $board) {
    foreach ($board as $boardKey => $boardItem) {
        if ($boardKey == "name") {
            echo "Название доски: ".$boardItem."\n";
        } else {
            echo "Треды:\n";
            $i = 0;
            foreach ($board[$boardKey] as $value) {
                $i++;
                echo "  ".$value."\n";
            }
            echo "  "."Количество тредов: ".$i."\n";
        }        
    }
}