> though presumably that's because it was linked from LessWrong

No surprise there, given that this experiment is discussed in Sequences, the link to the post present in the article you link to :).

Thank you! I forgot the name of the game, and it is totally unsearchable.

Zendo is fantastic. Watching people unaccustomed to its sort of problem-solving struggle with and improve their methodologies for being good at the game is really enlightening.