I don't know if this is the right section for this question...but I want to get into modding this summer and I'm interested in knowing which is the best game to mod for beginners. I am a student in high school and don't have a lot of knowledge in advanced programming topics such as inheritance, polymorphism and etc. I want to start modding for the educational experiences of it. So far a friend recommended Elders Scroll Morrowind and Fallout 3. I read that Crysis is pretty good but I want more options. In terms of game programming, I am making a pong clone but my computer died and when my new rig arrives I plan to continue development immediately. Thank you in advance.

Valve has quite the modding community. Their products are great.

Never dealt with Source, however I've heard its a chore.

My goal is more geared towards programming such as AI. Again, I am a noobie when it comes it modding so excuse me if I wasn't transparent enough. I guess level design is something that is also interesting as well. Keep the suggestions coming.