http://www.techradar.com/news/the-steam-halloween-black-friday-and-winter-sale-dates-have-been-leaked

Steam Sales are like busses, you wait ages for one, then three come along at once. And thanks to a leak on Reddit (that has now been deleted) we know the exact dates for the Steam sales that are coming up for the rest of the year. 

The Steam Halloween Sale is first up, starting in just a few days time, unsurprisingly straddling the Halloween weekend, so you can get your hands on some discounted games to play between trick or treaters and costume party preparations.