For a video introduction by the creator, Roberto Ierusalimschy who is a professor at the PontifÃcia Universidade Católica do Rio de Janro , watch the video: Small is Beautiful: the Design of Lua at http://ee380.stanford.edu.
Roberto has done several books on the language which are very helpful and interesting.
You might want to try seaside/smalltalk for something completely different: http://www.seaside.st/?_s=XBRlPkWQFO4mUh21&_k=uMS3uuIb...
Smalltalk is where the objective part of Objective-C came from. It is not at all a C based language itself though.
Sure I would like to have the time to play with OCaml / Erlang / Haskel but what I really want is the time to work on an exciting application!
Thats where the fun is. If I had the time to play with robotics, telepresence or virtual reality I would learn whatever language I would need to do it.
Languages, meh
?- exciting(prolog).
true.
Whether you'll actually use it for some bigger projects is questionable, but it's certainly a challenging task, just because it's a very different approach. And e.g. SWI-Prolog actually has a nice web package at http://www.swi-prolog.org/pldoc/package/http.html .PS: There were articles on HN in January about the 12 languages in 12 months but I don't want to look them up so I will provide you with the link I saved from them http://www.coderholic.com/12-new-programming-languages-in-12...
It's got all the power of JavaScript (which, in addition to its monopoly on browser scripting, is now a respectable server-side language thanks to Node.js et al.), it's very new (first source push was in December), and the syntax is just beautiful—even nicer than Python's, in my opinion. I've been totally thrilled since I've started playing with it, and I'm using it for some serious browser-based projects.
This book would be a good start:
http://pragprog.com/titles/btlang/seven-languages-in-seven-w...