One of the best archival features of speculativegrammarian is Lingdoku “a sudoku-like activity for linguists.” The first, and easiest, lingdoku works like this:
Using the nine IPA symbols in the [first] table, complete the [second] unfinished table. Each symbol occurs exactly once in the box, and no row or column may contain more than one symbol with either the same place or same manner of articulation.
Subsequent lingdoku get progressively harder: the second one involves a four by four grid and the addition of palatal place and lateral manner of articulation, and later ones are even more complex. Here’s a list of all the lingdoku and variations — note that each puzzle’s page also contains the solution to the previous one.
Any of the lingdoku are a fun way to practise the IPA! Here’s a clickable IPA chart and an explanation of manner of articulation, for reference.