Someone told me once, that programmers tend to learn one scripting language properly and ignore or dislike other scripting languages. Do you have similar experiences?
 I'm using Python as my choice for scripting for  few years, however, I'm sure that there are many existing and emerging languages that could impress the Pythonistas. Can you recommend scripting languages that would be interesting and useful to learn besides of Python?
I would learn a statically typed language with very powerful type expression capabilities and awesome concurrency.
One of the following would be a good choice (in order of my preference):

Scala
F#
Haskell
Ocaml
Erlang

Typed languages like the above make you think different. Also these languages have REPLs so they can be used as a scripting language although truthfully I'm not really sure what the definition is of "scripting" language is.
Python is missing good concurrency builtin to the language so knowing how to deal with concurrency for many python programmers is a challenge.
I have found that strongly typed languages scale better for big projects for many reasons:

Because types are so important they become an invaluable way to communicate the problem
Refactoring in these languages is much much easier.
Automatic Serialization is sometimes easier too (although for Haskell thats less true).
A lot less time spent on writing assertions on type checking.
Browsing the code is easier because most IDEs will allow you click on and go to different types
Learn a scripting language besides Python