Two big genre films are opening nationwide for the President's Day weekend; actually, they opened a day early (on Valentine's Day) to stretch the lucrative frame as much as possible.

JUMPER - a sci-fi adventure about teleportation, starring Hayden Christensen and Samuel L. Jackson - has earned a 15% rating (well down in "Rotten" territory) in a survey of 100 reviews (15, fresh, 85 rotten) at Rotten Tomatoes. Says Kevin Crust in the Los Angeles Times:

• Jumper seems half-done -- a long prologue building to a classic hero's journey or the launch of an antihero -- but comes to a screeching halt before it can begin either.

Finding far more favor with the critics was THE SPIDERWICK CHRONICLES, which has earned a 77% approval rating in a survey of 78 reviews (60 fresh, 18 rotten). Roger Ebert calls the film:

• A well-crafted family thriller that is truly scary and doesn't wimp out.