Whamageddon

Whamageddon is a game played during the 24 days before Christmas Eve in which players try to go from December 1 to the start of Christmas Eve as per European celebrations on the 24th December (midnight on the 24th December or 24:00 on the 24th of December) without hearing "Last Christmas" by Wham! If the player hears the song between those days, they are out of the game and have to post "#Whamageddon" on social media to indicate that they have lost. The exceptions to this game are that the player can only listen to remixes and cover versions of the song. Whilst not encouraged on the website, but technically still a part of the rules, a player can send another player the song, or play it to them so that the other player loses the game, although Whamageddon is described as a Survival game, as opposed to a Battle royale game.
History.
One of the earliest versions of Whamageddon appeared on online internet forum GTPlanet in 2010, under the name "GTPlanet vs. Wham! - Last Christmas". The rules are nearly the same, apart from the game having no defined start date and ending at midnight on 31 December, and the presence of the song within the discussion thread itself being prohibited. Comments from the site's users indicate the game had been played previously on other sites, so it's unlikely that this was the genesis.
In 2016, a Facebook page was created for Whamageddon under its new name and revised dates that the player takes part from. In 2017, the game gained a small amount of publicity on Boing Boing and Lifehacker. In December 2018, British stand-up comedian, Romesh Ranganathan posted a tweet explaining the rules of Whamageddon to his 416,000+ Twitter followers. Because of Romesh's tweet, mainstream and local news websites online also picked up on the popularity of the game.
Whamageddon is featured each year on PrimordialRadio as part of Dewsbury's afternoon show. This has daily updates from the radio stations' community for the losers and survivors.
Gameplay.
Rules adapted from the official website of Whamageddon.
Once a player has lost they are sent to 'Whamhalla'.
Usual places where players get knocked out tend to be cafes, shopping centres, drive-time radio, and Christmas work parties. When a player is unexpectedly knocked out, this is known as a 'Whambush'.
Alternative variations.
Other variations of this game exist, based on other Christmas songs. One features "Fairytale of New York" by The Pogues, and originated on Twitter in 2016. The only rules that apply to this version of the game is no "Poguerolling" (sending the link to friends online intentionally). As with Whamageddon, the player is out as soon as they recognise the song and accidentally hear it, whether it is in a supermarket or on the radio, or in another public place.
Since the death of Wham's George Michael on Christmas Day in 2016, the GTPlanet forums has transitioned using to Mariah Carey's "All I Want For Christmas is You" as an alternative challenge. This version of the game is termed "ApoCareypse", and all of the original rules apply.
In New Zealand, Snoopy's Christmas is sometimes used as the featured song.
Another version is WhamHunter where players get a point each time they hear it. This allows enjoyment of Christmas music and not having to worry when walking through a shopping centre or when the radio is playing in the car. The only rule is hearing it must be organic (ie dont have it on repeat).