I'm trying to learn as much about linux as I possibly can and I'm looking for some fun stuff to do, setting up different servers basically. Most likely I'll wind up writing some how to's on the stuff.
Here is my current list of things. (some i have already done, just need to go through it again and write the docs)
apache, php, mysql, perl
what else do you suggest.
Also aside from servers, do programming. Its fun and educational. Start with bash and python, maybe lisp, learn Java, C and C++, xhtml, php, etc.
Also, if you don't know it, learning to use both vim and emacs effectively is important.