You didn't play Fatal Frame I+II. That is scary.

Playing Fatal Frame late at night, alone, in a dark room...I agree, scariest game I've ever played.

The Penumbra series puts every other game I have ever played to shame. Highly recommended.
Call of Cthulhu and Resident Evil 4 both came close though.

This is silly I know, but Sinistar.
First time you play, You are just going along collecitng mining astroid. Suddenly some one yell "Coward I Hunger!" and then this thing jumps out at you from nowhere at eats your ship. I jumped out of my seat. lol
a great blog about it with sound from the game http://www.eod.com/blog/2009/10/sinistar/

Conquers Bad Fur Day! In the cemetary with the shotgun

You want scary? I will give you scary.
The original Test Drive on the Atari ST, where when there is no traffic it gets up to 7 fps, and when there is traffic down to 3-4 while at the same time you have rocks on the right side, police after you and a cliff on the left side. You are in a Ferrari doing over 200Km/h and try to pass a slow moving vehicle while the above conditions exist. At that moment a family station wagon appears coming your way and you have 2-3 frames to change course or kill a whole family!

Duke Nukem 3D scared me years ago when with God Mode and Jetpack I flew up, turned the jetpack off to crash to the ground and turned 3rd person perspective on (or came across a mirror?). That was scary at that time.

Oh right, sorry. Hey, I noticed you didn't play Penumbra 8(

Hehe, you'll love it. Don't forget to darken your room.

I love scarey games, and these look great--are they DRM free?
Also, I forgot to mention a game that scared me silly--Undying.

DRM free from the Site. I think the retail requires to enter key, but it's hell of worth it. Also available on Steam.

Yes, they are, if you get them from the official store. :) 20$ for the trilogy, awesome price!
Let us know how you do (if you shit in your pants or not). :p /joke
By the way, Skreczi, can you please look at this?
http://www.gog.com/en/forum/general/gog_any_chance_of_scaring_the_out_of_us

Condemed is pretty intense