Techland announced today Summer with Dying Light, a two month long campaign that'll see the first-person post-apocalyptic zombie-survival game supported with six weeks of "frantic weekend events."
Each weekend, starting tomorrow July 4th and running through August 30, Dying Light will host a one-off in-game event with special rules or mechanics. This weekend (July 4-5), is Spider-Crane weekend — "unlimited grappling hook shots and almost no fall damage."
The Harran Marathon, which I assume will be related to the game's parkour element, will take place the following weekend from July 11-12. Beyond that there are four more unannounced events scheduled for July 15 – 16, August 15 – 16, August 22 – 23, and August 29 – 30.
In addition to Summer with Dying Light, Techland is also running a Drink for DLC campaign, where players must post pictures of themselves drinking water in order to unlock future free DLC. This was created in jest of Activision/Bungie's Drink Red Bull campaign, which required Destiny players to purchase specially marked cans of Red Bull in order to obtain a code that unlocks an exclusive quest in the upcoming expansion The Taken King.
Beyond this event, Techland maintains they will continue to support Dying Light with a mix of free and paid-for DLC.