[Waterluvian]

About 15 or so years ago a roomate and I recognized this issue and created a simple solution that worked for us. A Google sheet where we would list games we completed and give them 5, 10, or 15 points subjectively based on the size of the game. At the end of a school term whoever got the most points would pick a dinner (take-out, dine-in, etc.) and the other would pay. For us that's all it took to break out of the habit of playing the same 2 games all the time.

I'm sure many of you are being fastidious engineers and immediately thinking about all the failure modes. But that's the delight in something so simple: we didn't have to worry about everyone else's failure modes.