Advent challenges

Twenty-five doors, from 1 to 25 December: behind each one is the daily challenge of one of five games, taking turns: Klondike, FreeCell, Spider, Sudoku and Minesweeper, in their Christmas look. A door's puzzle is the same for everyone, and it can always be solved.

How it works

• Each door opens on its day. Door 1 on 1 December, door 2 on the 2nd, all the way to Christmas. If you really cannot wait you can open one early, as with a paper calendar: we only ask whether you are sure.
• Past doors stay open. Miss a day and you can play its puzzle whenever you like, into January and beyond.
• Your result is yours to share. Solve a door and you can send your time and your streak to whoever plays with you, without giving the solution away.

Free, with nothing to install

It plays in the browser, on a computer or a phone, with no sign-up and no download. Your results stay on your device.