You'll be able to download and play Overwatch for free next weekend on PC, Xbox One, and PlayStation 4, Blizzard has announced.
The Overwatch Free Weekend, to give the event its wildly unimaginative official name, will run from 7pm on November 17th to 7:59am on November 21st in the UK - that's 11:00am PT on November 17th until 11:59pm PT on November 20th in North America. It will include all 26 heroes and 16 maps, available in Quick Play, Custom Games, and the Arcade.
If you choose to get stuck in, you'll be able to earn Loot Boxes, unlock various customisation options, and level up - and you'll be able to keep any progress you've made over the weekend, should you decide to purchase the full game after the event is over.
To play for free on PC, you'll need to download the battle.net desktop app, register an account, and install the full game. It's not a lot more complicated on PlayStation 4 or Xbox One, but you will need to have a PlayStation Plus or Xbox Live Gold membership to participate - so you could, I suppose, quibble the use of the word "free".
If your interest is in any way piqued, you can find more details on the Overwatch website.