SimCity 4 is a simulation game in which the player, as mayor, builds and runs a complex and dynamic city. SC4 was released in 2003, so it's old by computer game standards. There is, however, still an active base of users who still play and even create new content for the game (mods). I've written about my experience using mods in Skyrim, but modding SC4 has been a whole new playground.
One mod I found for SC4 adds new, high capacity buildings that allow cities to grow much larger than in the vanilla (unmodded) game. I downloaded this mod and installed it, but found out that I would need to find other files that contained the actual new buildings. For each building, there was a 'Lot' file that defined the area and placement of the building, a 'BAT' file that determined the structure, a 'Texture' file that determined what the building looked like, and several 'Prop' files to add detail. For some reason, these four file types were all in different places and had to be hunted down and compiled over the course of several hours.
I felt a nice sense of accomplishment when I finally got a modded building to appear in my city, but was it really worth it? I don't know how much these mods will really improve my SimCity 4 experience. It might be that the real value I got from this was practice with problem-solving and troubleshooting computers. It's something, I guess.