Pretty much any new language has an online interpreter these days, so you can try it without even having to install anything.
For future reference, I collected all the links here:
| Clojure | http://tryclj.licenser.net/ |
| Scala | http://www.simplyscala.com/ |
| Python | http://try-python.mired.org/ (or http://trypython.org , but that one needs Silverlight) |
| Ruby | http://tryruby.org/ |
| Go | http://golang.org/ |
| Erlang | http://www.tryerlang.org/ |
| Groovy | http://groovyconsole.appspot.com/ |
| Lua | http://www.lua.org/demo.html |
| NodeJS | http://jsapp.us/ |
elmarschraml.com 