Obviously, you need some creepy horror RPGs to play this week. The Bundle of Tentacles lets you get entangled by a ropy, squirming mass of them, including Trail of Cthulhu and several Call of Cthulhu supplements.
Bundle of Tentacles is a pay what you want ($7 minimum) collection of RPG PDFs. The base set includes a pair of books by Kenneth Hite exploring the Cthulhu mythos, Cthulhu 101 and Dubious Shards. The star attraction, though, is Hite's Trail of Cthulhu, a Lovecraftian RPG built on the GUMSHOE system. It's an ideal system for investigating the nameless horrors that have crept into our reality from beyond time and space.