An email was posted on Steam reddit showing Steam customer service might have either teased the date of the sale or accidentally mention the date.
Well, I doubt he made a mistake since he placed a smiley after.
For those who don't know...
Every year Steam starts a big summer sale that brings great titles down to really low prices. We are talking about prices all the way down to 75% off, with different deals every day. Last year, they even included flash deals that only last around 8 hours each time. Even a community deal was introduced allowing customers to vote among the three titles that get to go on a big discount for a few hours.
So... it could be coming tomorrow. Damn, I'm not sure I'm ready to spend all that money on games I'll never play, are you?