*edit. I should note a good modding api and/or editor is great for any game.
I started programming though making mods for battle for middle earth 2.
However, we must make sure to keep in mind the ways in which capitalists will exploit the goodwill of developers and free software wherever it may be.
these projects have really impressed me, for years they were only playing with animations & the combat calculations to make it feel different; now there's new combat functions with the animations like attack combos i really want to try them out... god its a lot of effort to set up tho