Criboku is a daily cribbage-based logic puzzle. You have to fill in a grid from a given pool of cards to make cribbage hands. Each hand's score must match the values around the grid. Some cards and scores are given, you have to work out the rest.
There's a new puzzle every day, and they get harder through the week. There's a help page that includes a primer on cribbage scoring. If you get stuck, there's a Hint feature that walks you through the logic needed to place each card.
My favorite parts are the bits nobody sees. My generation method guarantees each puzzle has a unique solution, and can be solved just by deduction, no guessing and backtracking. Also, the answer never gets to the browser, because it's not needed. Thanks to the uniqueness guarantee, we know the solution has been reached by just checking the scoring and pool constraints.
It's free, no ads, and no account needed.