Oh, hello. Valve are running a Steam sale to celebrate the launch of Steam Machines, offering substantial discounts on games that work on SteamOS including 50% off Alien: Isolation, 40% off Binding of Isaac: Rebirth and 33% off Ark: Survival Evolved, and much more.
There's 45 discounts on offer in total, including ridiculous bargains like XCOM: Enemy Unknown for £3.74 and bundles like both Metro games for £6.24. You can also get Fez for £1.39, Banner Saga for £3.74 and Roundabout, which I bet you missed when it was released earlier this year, for £2.74.
I'm not going to list the others, but these are good discounts. Of course, you might want to skip them and instead gamble on better offers appearing in a few days or weeks with Steam's inevitable holiday sale kicks off. Those will likely come with some strange, barely comprehensible metagame however, whereas these are just good games for cheap.
I don't know whether Steam Machines themselves are a good deal, but John and I both have Steam Links and Steam Controllers and both of us have experienced difficulties with those. We should have a proper review/verdict chat for you sometime in the near future.