DayZ just had it's 10th anniversary! It is just a great game, complicated and unwieldy but man you can do pretty much anything.
Obviously there's the zombies, that's a given, but everyone I meet is playing a different game. PvP can be bonkers... or you can live as a woodland hermit; foraging mushrooms and fruit, hunting animals and fashioning outfits from their pelts. The possibilities are endless!
An active modding community and regular developer updates means it never gets stale. Fantastic platform, I think it's neat.