Steam Summer Sale 2015 [over]

Yep, it's that time of year again. So here's a thread to help keep track of the cream of the crop – a place to post the deals you reckon shouldn't be missed, or that you'd like to see everyone else pick up for some multiplayer, or maybe the ones that aren't on a Daily or Flash sale yet but everyone should be on the lookout for when they are.

Here's a few I've bought / am looking out for:
- Bloody Trapland (4-player co-op platforming, super-cheap; I, Kitty and Ter own it)
- The Darkness 2 (has a 4-player co-op campaign; I've got the demo on my to-do list)
- XCOM (it's on daily right now guys seriously you're missing out http://store.steampowered.com/app/200510/)
- Serious Sam: The Second Encounter (85% off right now and it's not even daily)
- Distance (I and Ter own it right now, and it's seriously the best racing game ever; if it goes on daily/flash sale get it get it http://store.steampowered.com/app/233610/)

Edit: Also watch out for Tabletop Simulator; if it goes low enough it will immediately become a compulsory purchase.

Please add Robot Roller-Derby Disco Dodgeball to the list. ^_^ It looks insanely fun, and the instant it goes on daily, I'm going to pick it up, as I suggest all of you do as well.

Also Nidhogg is 90% off right now and looks somewhat fun. My guess is it'll pop up for that price again sometime later in the sale.

Sonic & All Stars Racing Transformed is currently part of the Flash Sale & could also be fun as a mock-Mario Kart night, if you're willing to look past the logic of Sonic needing a car P:

Lethal League is on daily right now, and I've been meaning to pick it up. The packs, particularly the Two Pack, looks like a VERY good deal right now.

also you should watch for when LISA goes on flash or something, I can't stress enough how good of a game it is