It's well past Halloween, and two scarefests are still haunting theaters. The Grudge has been in the top 5 for three weeks, while the gory indie Saw has earned $35.4 million in two frightfully good considering its $1 million budget. ''The only way our movie could become relevant both to the press and to the consumer,'' says John Hegeman of Lions Gate, which distributed Saw, ''was to be tied to Halloween.'' That success has bred Saw 2, due October '05, and highlights the holiday's importance as a key release date (Halloween: the new Christmas!). Which strikes the guys behind Saw two 27-year-olds from Down Under as funny. Says director James Wan, ''We don't celebrate Halloween in Australia.'' Now maybe they will.