Cards Against Humanity doesn’t approach its marketing efforts like most companies. Nominally, they sell a highly irreverent card game where players compete to find the most outrageous response to a prompt from their hand of cards. In practice, the Chicago-based company has used its past successes to finance a series of elaborate pranks to entertain its ardent fanbase and transform purchasing a casual party game into an experience…which is a good thing, since they give the game away for free on their website (some printing required). Two years ago they celebrated the holidays with a pay-what-you-want expansion pack, and then released an infographic breaking down how much people paid and donating the proceeds to charity. To encourage players to buy the expansion sets, the company sold an extra-long box for holding the game, The Bigger Blacker Box, to store the cards. Without telling anyone, they hid a secret card in the inner lining of the box. For their Black Friday sale last year, they increased prices. When they took out advertisements at last year’s PAX East, they used the platform to promote their made-up company, PWNMEAL: Extreme Gaming Oatmeal.

All of these efforts pale in comparison to the company’s Holiday Bullshit campaign. Last year, Cards Against Humanity asked 100,000 people to give them $12 in exchange for 12 mystery gifts from the company as part of its 12 Days of Holiday Bullshit. As thanks, the company donated $100K to DonorsChoose.org, sent out an early edition of a sex party-themed card game, mailed limited edition customized Cards Against Humanity cards, and even sent fans a lump of coal. And hidden within each mailing? A fiendish puzzle that took fans working together on Reddit’s holidaybullshit subreddit months to solve. Holiday Bullshit is back once more, promises to deliver an even harder puzzle than before.

The inaugural Holiday Bullshit puzzle was not easy. Fake time codes on each of the envelopes hid semaphore messages telling puzzlers to look for secret braille messages hidden in the borders of their cards. This in turn led players (through a highly convoluted process) to two Cards Against Humanity cards, and a website with the solution. As a reward for being first to solve the puzzle hunt, the team sent Reddit user Lets_Go_Flyers copious amounts of alcohol and an autographed set of everything Cards Against Humanity made (prior to the holiday season).

For its triumphant return, Cards Against Humanity’s Holiday Bullshit is abandoning Christmas to celebrate Ten Days or Whatever of Kwanzaa. For $15, the team is preparing ten mystery gifts throughout the month of December for the first 250,000 registrants. And like its previous incarnation, the Ten Days or Whatever of Kwanzaa mailings will include an online puzzle that Cards Against Humanity co-creator Max Temkin described to the Chicago Tribune as “the hardest puzzle ever made.” This year the puzzle experience was designed by Mike Selinker, who has worked on a number of non-traditional puzzles including hiding a secret message in the spine of every issue of WIRED Magazine in 2012, organizing a cross-country manhunt for journalist Evan Ratliff, and a publishing a narrative puzzle adventure book.

This promotion is limited to residents of the US or Canada (although Canadians will need to pay an additional $10 to cover increased shipping fees), and is limited to one subscription per household. Almost 100,000 slots have already been claimed in its first day on sale, so act soon if you want to participate. Go to HolidayBullshit.com to subscribe to the Ten Days or Whatever of Kwanzaa, and follow along with the puzzle solving efforts at the holidaybullshit subreddit.

Update: click here for a description of the 2014 Holiday Bullshit puzzle and its solution.