WSJ's Varsity Math is a weekly dose of challenging puzzles, created by the National Museum of Mathematics. The museum's Glen Whitney guides viewers through "Instant Interrogation," a game he created.

Critics and puzzle fans say it might be one of the best games this year, which is surprising because it makes you do math. And it’s not even just regular math; it’s math with made-up rules.

The New York Times has a new web game out this week that, depending on how well you did in high school algebra, may or may not be your new favorite thing. Digits, which the paper launched Monday ...