quake/quake 2 mods

What are a couple of definitive custom levels I should try for Quake and Quake 2? And is there any point in downloading the /idgames2 mirror? (I already have /idgames)

There is a mod for Quake II that in my opinion is the best mod for any game ever. It is called Gloom and I don't think many people play it anymore but it's the best mod of all time (In my opinion). Look it up..