repl.it
Have you tried http://repl.it? It supports Ruby, Python, Lua, Scheme, JavaScript, Javascript.next, CoffeeScript, QBasic, Forth, Move and Kaffeine.
It also supports these esoteric languages: Emoticon, Brainfuck, LOLCODE, Unlambda and Bloop
From their FAQ:
What is repl.it?
It is an online environment for interactively exploring programming languages. The name comes from the read-eval-print loop, the interactive toplevel used by languages like Lisp and Python.
Is repl.it open source?
Yes! You can explore the code and contribute to various parts of repl.it through our GitHub repositories.