Freaks and geeks unite! America's largest convention for sci-fi and fantasy fans, DRAGON*CON fills downtown with plenty of Trekkies ("Have you heard anything about the new 'Enterprise' show?") and X-filers ("What was Chris Carter thinking this season?"), along with other comic book and film fans AUG. 31-SEPT. 3 The "Guest Writer of the Millennium" is popular sci-fi writer Harlan Ellison with Master of Ceremonies Anthony Daniels, aka C3PO. Costume contests, music acts, an art show and workshops will keep the Vulcans off the street until the wee hours of the night. $75 for all four days of the convention. Events take place at the Hyatt Regency and Marriott Marquis downtown. For a complete list of events and times, visit www.dragoncon.org.