The effects of boredom in October
http://www.youtube.com/watch?v=EOzPITA9TPY
So you can guess where this idea for this map came from(wanting to do a map for Halloween).
But ran out of ideas and lost interest in the project 
Here is what was done.
(on a side note, have you ever tried to make a scare/spooky/horror/spoopky map for portal 2?)
[spoiler]My Steam Profile http://steamcommunity.com/profiles/76561198027454516/ My YouTube Page http://www.youtube.com/user/GLaDOSCUBE?feature=watchMaps[/spoiler] Maps
[spoiler]SP Bounce http://forums.thinking.withportals.com/downloads.php?view=detail&df_id=1753SP The Part Where http://forums.thinking.withportals.com/downloads.php?view=detail&df_id=2287[/spoiler]
Yes, I have made a scary map called "killer's office", but it has a tendency to randomly crash on other people's computers apparently, and is on my workshop but not here. Yours though.... That's is some seriously creepy material. That moaning adds quite a bit. I'm working on 2 other projects on the side, Timmy and Paranoia, and have one canceled creepy map, enderchell.
If you are considering releasing or working on that map though, I would play it.
Aperture Science: We do our science asbestos we can!
Yeah I'm working on a surreal horror map that was originally planned for Halloween. But given that a) I wasn't satisfied with the amount of weirdness currently in it and b) I didn't see much other Halloween-related activity this year, I decided to finish it properly and release it later.
That video is pretty good. Looks like a very good exploration / survival horror themed map.
Other Portal 2 maps: Medusa Glare
Portal 1 maps: Try Anything Twice | Manic Mechanic
Same thing here. I planned to release Hide on the 31st, but I ended up running into some bugs, and later decided to add another entire section to the map. Might make a <Holiday Name Here> map though!