Holiday B.O. hangover bugs Y2K.(the motion picture boxoffice for the year 2000 is underway, with new films being released soon after New Year's Day)

HOLLYWOOD To paraphrase the title of a 1970s cult classic, we're now in Box Office Race 2000.

After the Jan. 7 weekend break from any new wide releases, the studio's annual dash for cash began last weekend with bows of New Line's "Next Friday" (which opened Jan. 12), MGM's "Supernova" and Gotham and L.A. engagements of Warner Bros.' family pie "My Dog Skip."

Plus, the biz is back in the holiday spirit, as Jan. 17 is Martin Luther King Day, when most schools are closed and many Americans have the day off.

Since becoming a federal holiday about a decade ago, the date has gained potency as a film launch pad. Par's "Varsity Blues" bowed with $17.5 million last MLK weekend. In 1997, "Beverly Hills Ninja" karate-chopped all rivals with $12.2 million.

The two films that widened out over the weekend of Jan. 14 have had successful platforms thus far: Universal's "The Hurricane" and Sony's "Girl, Interrupted."

With $3.2 million in hand after two limited weeks "Hurricane" went into almost 1,500 theaters Jan. 14. Momentum from limited engagement is seen carrying over at least for one wide …