CLOCC - the Common Lisp Open Code Collection (link) is self-contained lisp code that provide various functions. Including the ability to parse xml with xml.lisp. Very interesting.
Oh and the net.list includes such interesting functions as resolve-host-ipaddr ipaddr-to-dotted dotted-to-ipaddr.
Sweetness. Granted I didn't see something like UDPServer but, meh, I think it might be something trivial to write.
On further musings, maybe it's time to revist that atom blogger mode in emacs-lisp. Something about Title: and then the URL: entry point that's just bugging me. That should be simple, but maybe there is something in the code that I'm not reading correctly.