Penn grad Seth Berkowitz started Insomnia Cookies, a late-night cookie-delivery biz, during his junior year. Nine years later, he's fueling student munchie sessions at schools including Purdue, Syracuse, Yale and N.Y.U. But why should kids have all the fun? A few weeks ago he opened a Center City bricks-and-mortar location, where, gooey, soft, hit-the-spot cookies are pulled fresh from the oven until 3 a.m. daily. The chocolate chunk is the most popular, but don't miss the s'mores deluxe - a chocolate cookie dotted with graham cracker and melted marshmallow. Extra credit: Insomnia has cookie catering and delivery and sells milk.