I heard something like this somewhere; might even be commercially available. Seems like it could be easy to implement with cards with words on them, and a spot to record difficulty level (starting value=estimated difficulty; +1 each time it’s asked but not in reposne).
Stack of cards with a single common word on it.
Draw card.
Ask Alexa one question; word in response? Score! Score the difficulty level of the card
Word not in response: increase difficulty level on card +1
