Steam News has word on a new patch that's now live in Team Fortress 2, among other things adding the "Halloween 2011 Event" to the teamplay shooter. There are further details on the Very Scary Halloween Special on the Team Fortress 2 Blog, where word is:

Long story short, we guarantee you that nothing's going to scare you this year. There will be no ENORMOUS HAUNTED EYEBALL to terrorize you around an island filled with tons of SECRET LOOT, and a GIANT SKULL! There will be approximately zero percent chance of you getting your trembling hands on a spooky costume FOR EVERY CLASS! And we certainly wouldn't DRAMATIZE THE BACKSTORY of this hypothetical scary update with a FEAR-CHOKED TERROR-COMIC!