[Cryo]

You'd basically have to make either make one PHP file and have it run say, at the top of the hour and check the time to decide if it should open or not. Or you could two two and make one open and one close. An example file would work like this...

One file for closing...

PHP Code:

// Close the Forums

    $close_SQL = "UPDATE tableprefix_setting SET value = 0 WHERE varname = \"bbactive\"";
    $close = mysql_query($close_SQL);

    $close_txt_SQL = "UPDATE tableprefix_setting SET value = \"Our forums are currently closed but will reopen at 8:00am EST.  Thank yoU!\" WHERE varname = \"bbclosedreason\"";
    $close_txt = mysql_query($close_txt_SQL); 


Another for opening...

PHP Code:

// Open the Forums

    $open_SQL = "UPDATE tableprefix_setting SET value = 1 WHERE varname = \"bbactive\"";
    $open = mysql_query($open_SQL); 


You would then go into your vB admin panel and, after uploading these, run them at the times you would like to open and close the boards respectively. Of course, this is extremely rough (you have to change the "tableprefix" to whatever your tables start with, and you'd also have to do the database connections, etc), but this should work.

You could probably setup some hooks to check if the time fell two times when the page loads too and just refuse the user.