November 11 is Singles' Day because 11/11 is made entirely of ones, a tradition that started in China as a jokey excuse for blind dates and parties where singletons could meet. It's become a day that's more about shopping thanks to e-commerce site Alibaba using it as an excuse to throw a sale, and now it's the world's biggest online shopping event, with almost $US 31 billion made last year.
Steam are having their own Singles' Day sale right now, with a mix of singleplayer and multiplayer games being discounted. It's a pretty eclectic selection. For instance, you can get Divinity: Original Sin 2 for 45% off, a bundle of Telltale's Batman games for 67% off, or Dragon Ball Xenoverse for 80% off.
The Singles' Day sale runs till 8am Pacific on November 12.