The interior of downtown San Diego's Fifth Avenue Financial Centre is so antiseptic that it's probably a front for a top--secret hospital zone or an experimental lunar colony or something. Glare from pristine floors and walls blinds you into submission, making it tougher to navigate your way to Alex's Brown Bag, an archetypal little eatery on the first floor. Alex's even sports the same faceless signage that the business offices do; if it weren't for the tables and chairs in the adjacent foyer, you might even walk right by it.But you'd be making a mistake if you did. Alex's, after all, brands itself the local home of the Philly cheese steak, a fabled, fantastic sandwich invented in Philadelphia around 1930 as a Great Depression comfort food. The name pretty much says it all--this is a tangy collection of thinly sliced steak topped with mozzarella and served on crusted bread; you can pretty much get it with any condiment you want (fried onions are the way to go), and it comes with a pickle slice roughly the size of an Olympic javelin. A little more than $9 gets you this little bit of history and a big fat drink. Salads and omelets are among the other featured fare and are somewhat cheaper.A grade--A butt--crack once tried to rob me in Philadelphia (I ran like hell when he wasn't looking), so I'm over the moon that the Colorado Rockies have knocked the Phillies out of the playoffs. As long as the world has a good Philly cheese steak, it hardly matters what happens to its namesake city. You can get one by showing up at Alex's, 2550 Fifth Ave., Suite 171, between 7 a.m. and 5 p.m. Mondays through Fridays; and you're welcome to call ahead at 619--231--2912 or look up the menu at www.alexsbrownbag.com. And rest assured that in that building, the sanitation is beyond reproach.