I'm mostly asking this question because I don't know how to phrase it well enough to get relevant google results. I'm very ignorant about modding, but I know that in the general case it's a lot easier than doing your own stuff from scratch. Are there any good games out there that are mod-able that would help a beginner practice some 3D programming (as in, collision detections, transforms, etc in 3D)? If someone has already asked this question and you can find it, then I'd be very thankful for the link, and I'm sorry for posting something that has been answered. If you don't completely understand my question, I'd be happy to rephrase it if you let me know.