an extremely long time. business weeks being a time frame used as a shipping time estimation, i.e. your package should arrive in 6 to 8 business weeks. a business week consisting of only business days, not weekends, thus being longer than a normal week. in effect, forever.
girl: how long will you love me?
guy: 6 to 8 business weeks, baby!
girl: awwww...i'll love you forever, too!
dave: how long are you grounded for?
ken: 6 to 8 business weeks!
dave: damn! well, it's christmas now, that means you should be out by...lets see...4th of july maybe?
ken: probably more like labor day!