Clue O'Clock is a small daily guessing game, made by one person, published for free.
Most guessing games give you the whole puzzle at once and ask you to grind at it. This one does the opposite: it gives you almost nothing, then relents, one clue at a time, until anybody could get it. The interesting part is not whether you solve it — nearly everyone does eventually — but how early you were willing to commit.
Every mystery is built backwards from its answer. The fifth clue is written first, and it is deliberately obvious. Then each clue above it takes something away, until the first one is a sentence that is completely true and almost completely useless. The last thing written is the payoff line at the end — the fact that makes the answer worth having found.
Answers are always things a person anywhere in the world might reasonably know: objects, ideas, places, a few famous names. Nothing that depends on having grown up in one particular country.
The game is paid for by advertising. There is one optional video ad, offered in exchange for a free clue, that you never have to watch. That is the whole business model, and it means the game can stay free and account-free.
Corrections, arguments about a clue, or an idea for a mystery are all welcome — see the contact page.