For the longest time now, I have been trying to play through a Pokemon randomizer nuzlocke.
It's like a regular nuzlocke challenge (1. You can only catch the first Pokemon you find in an area 2. Once a Pokemon faints, you have to release it) but with a lot of variables randomized by a ROM patch. I have it so the wild/trainer's Pokemon, held items, movesets and abilities are completely random.
So for example, in my most current game of Emerald version, my starter was a Poliwhirl, with Inner Focus as its ability, and it knows Bind, Astonish and Twineedle. I just caught a Cacnea on the first route for my first caught Pokemon
It's incredibly fun and addicting, but pretty much impossible to beat. I've maybe gotten 6 badges at most, after 20+ tries. I will often play in spurts and then have to put it down because it becomes so frustrating sometimes.
EDIT: Also add pretty much every arcade game I ever tried to play too