I hadn't seen those Red Hat quizes before. I took the admin and the security one... Pretty much aced the admin (only had a 3 in two sections (jumpstart and something else), 4's for everything else). I didn't do too bad on the security one, but screwed up the ones I figured I would (DNS and BIND, SELinux, PAM, and VSFTP, since I don't "really" use any of them). I mean, I use PAM for things like password complexity, rules, and such, but don't really know off the top of my head what the differences are between required, sufficient, etc... And SELinux is simply a headache that we disable immediately.
As for digging into things, to learn how they work, I did most of that by fooling with one of the early CD distributions trying to figure out how to install it to a hard drive, yet still act the same way it does on the CD (i.e. only mounting the disk in read-only mode, creating the ram drive, mounting the compressed image file from the hard drive to the ram drive, etc.). Had me learning how to dig into the initrd.img file, etc.. Was a fun time to be honest.