Halloween is my favorite holiday so I usually play at least a couple games for it throughout the month.

I wrote a couple related articles that I'll post if you guys don't mind. I always threads about blogs and such so I figure it's okay. Besides, GOG is mentioned part two since as far as I know here is the only place to buy AITD 1-3 and Sanitarium.
http://www.meodia.com/Retro-detail/games-to-play-for-halloween-part-1/
http://www.meodia.com/Retro-detail/games-to-play-for-halloween-part-2-2/

Thanks to anyone to checks them out!

What are your favorites, doesn't have to be horror games. Anything related.

I have also played:
Amneisa/Penumbra
Lone Survivor
Silent Hill series

Still need to play:
Clock Tower
Phantasmagoria
Waxworks

This, my good man.

Also, the Thief series.

No love for The Suffering ? :(

That would be one I need to play. That one is free now isn't it? I'll check that one out, looks interesting.

REmake (Resident Evil Remake) for delicious Crimson Heads.

Eternal Darkness for sanity meter.

"Secret of the Magic Crystals"

just for self punishment

It used to be free, with sponsorization from the U.S. Airforce, but I'm not sure if that's still the case. I downloaded it from Softonic, but couldn't make it work :(

But how...?

It Isn't as a direct sponsored download, but this version is still available from several sites like this: http://www.shacknews.com/file/12350/the-suffering-free-game

http://en.wikipedia.org/wiki/The_Suffering_%28video_game%29#Freeware_release And that version works for you? Because the one I downloaded just wouldn't connect to whatever the hell advertising I was supposed to see.

If you're a fan of Brit-horror (A Warning to the Curious, The Stone Tape, Sapphire and Steel, some episodes of classic Dr. Who, etc), then I recommend Barrow Hill and Dark Fall: The Journal.

No idea, am at work and can't try it out, just followed a long from wikipedia :)
Found this on Gamershell, seems like that the current IP Holder pulled the free version everywhere.
http://www.gamershell.com/download_33314.shtml

Yeah, but sponsored by the USAF... lol.

Gabriel Knight series?

There are too many good halloween games to count
http://www.grasz24.pl/publicystyka/strach-w-to-grac-przeglad-najbardziej-przerazajacych-gier-cz-,1,1,10844
here I have mentioned some of my favorites (text is in polish)
like Eternal Darkness, Forbidden Siren, Fatal Frame