Wow, it never ceases to amaze me the things that people achieve in their spare time. That video above is a very good example of showing what the modding community has been able to do, basically nothing there is in the vanilla game.
The skybox/atmospheric effects, wet track, rain on the screen, the helmet cam and more are available such as multiple working light sources... guess I'm just voicing my appreciation, these people have greatly expanded the possibilities of this game and our enjoyment of it. None of them had to do any of this, but they did.