There are times when we over-play games to the point where we don't find them fun anymore, or simply outgrow the conventional way to play certain games - when that happens, some people may just decide to stop playing the game altogether, but sometimes, people make their own creative rules for the game, to either make an otherwise simple game more challenging, or just to play it in a different way.
Perhaps the most well-known example of this over here on PC is the large selection of Pokemon challenges - from Nuzlocking to mono-type challenges, players have come up with tons of creative ways to make Pokemon games more interesting and difficult.
Other examples of such challenges -
We all know the Sims as a rather casual franchise of games where you can go about living a relatively mundane life, but some players create elaborate scenarios and challenges that make the games more hectic and difficult (and in most cases, hilarious), like the
Insane Asylum Challenge or
Teen Runaway Challenge.
Another interesting thing some people experiment with is to take an open-world action RPG like Skyrim and just.. live like an NPC. Sort of. It's kind of the reverse of the above two examples, but it's hard in its own right, depending on the rules you set for yourself. Additionally, there are a number of mods to help you enforce such rules, like hunger, thirst and sleep mods (and maybe add some quests so you're not just living aimlessly forever). When you're not out aiding Jarls and slaying dragons, money can be hard to come by, so this is a different sort of challenge.
Personally, I tried living as a huntress in Skyrim, where I would only hunt animals for pelts to sell, and I also had a hunting guild mod downloaded, so it added some quests and a bit of a story to it - it was an interesting experiment, and a nice break from the usual story line.
How about you guys - have you ever added your own rules to a game, and played it in a way it wasn't meant to be played?