Enums and Interps - explanation?

Hi All

I hear people talk about Enums and Interps. I followed a TUT that used an Interp, but I did not know why I used it.

I know the descriptions for these are in the docs, but i would like to know in idiot terms; what they are, how to use them and what their main features are?

I thank ahead of time any who answer.



Found this, but still not much help.

Also found this, helps a little, but spends more time doing a tut on recoil