Tired of ASP.NET, which of the following should I learn and why?
Nobody seems to be voting for groovy. I'd go for that. I don't know anything about grails, but groovy the language is pretty cool. In the past nine months at my job I've been required to learn python and ruby. In the process I also took some time to understand groovy. groovy is the language that had me hooked before I finished reading the first chapter of Groovy in Action.  
Ruby is the one I'm actively using now, and while I did nothing but python for six months that's my least favorite of the bunch. Python is not a bad language per se, I just didn't enjoy using it. I find ruby to be a very pleasant language and am glad I had the opportunity to learn it.
Fully learning javascript might be the more practical choice, but I'd still vote for Groovy. I'm anxious to find an opportunity to use it at work.
Which of the following technology is easy to learn and fun for developing a website? If you could only pick one which would it be and why

Clojure/Compojure+Ring/Moustache+Ring
Groovy/Grails 
Python/Django 
Ruby/Rails
Turbogear
Cappuccino or Sproutcore
Javascript/jQuery