lol i hate it when people say scray movie <.< it's been a good while since any movie has scared me...

but i know what you're asking so i'll answer...

most any modern zombie movie (resident evil, dawn of the dead/land of the dead, 28 days later) 1408 is pretty damn good as well... i suppose waking up and being jim carey in 23 could be really frightening so i'll list that as well... the new amittyville horror movie is good too...

actually i take that first statement back... night skies... scared the LIVING SHIT outta me.. i believe in aliens... and it's based on true accounts, and even more so, it's not one or two people can can collaberate those lights in the sky (the stories of the 6 lost teenagers however would be easier to 'fraud') it's an entire fucking city....

On March 13th, 1997 one of the largest UFO sightings ever recorded took place across the southwestern United States. The event became known as the 'Phoenix Lights' and was witnessed by community leaders, members of law enforcement, as well as thousands of everyday citizens. This true story, based on transcripts from actual hypnosis-therapy sessions, finally reveals what happened after the infamous incident ended and how six people, stranded by chance on a forgotten road, encountered more than just lights in the sky
Night Skies (2007)

Phoenix Lights - Wikipedia, the free encyclopedia

read the wiki page, tell me you don't wanna know more...