Oh, waah, waah. It doesn't require registration at all; it just doesn't let you post with a blank "Name" field. Thirty second Ochiba hack to allow anonymous posting:

1. Open includes/post.php

2. Find line 53:

    array_push($errors,$ERRORS["namerequired"]);

3. Replace it with these two lines:

    $name="Anonymous";
    setcookie("name",$name,COOKIE_EXPIRES);

4. Save

Note that I haven't actually tested this, but I don't see why it shouldn't work. Either way, you can still just put random characters in the "Name" field. That's nothing like a reg-only board.