Online REPLs

• A list of a bunch: http://repl.it/ and http://news.ycombinator.com/item?id=3056490
• Kerning http://type.method.ac/

Tutorials

Ruby

• http://tryruby.org

Python

• http://try-python.appspot.com/
• http://www.trypython.org/ requires silverlight
• http://people.csail.mit.edu/pgbovine/python/tutor.html#mode=edit

Redis

• http://try.redis-db.com/

Clojure

• http://tryclj.com/
• http://www.4clojure.com/

Haskell

• http://tryhaskell.org/
• http://haskelllive.com/

Erlang

• http://www.tryerlang.org/

MongoDB

• http://try.mongodb.org/

Scala

• http://www.tryscala.com/

Fiddling

Ruby

• RubyFiddle

SQL

• SQL http://sqlfiddle.com/

Node.js and jasmine

• https://github.com/benrady/jezebel

Javascript

• http://jsfiddle.net/
• http://jsbin.com/
• http://rocktronica.github.com/tmpltr/
• http://www.jshint.com/ linting
  • packer: http://dean.edwards.name/packer/
  • decompressor: http://jsbeautifier.org/

Jasmine

• http://try-jasmine.heroku.com/

Coffeescript

• http://coffeescript.org/

Regular Expressions

• http://rubular.com/
• http://rubyxp.com/ (I really like this)
• https://github.com/martinisoft/graffiti
• http://rentzsch.github.com/JSRegexTeststand/
• Regular expressions fiddle

Other

• vim color schemes http://bytefluent.com/vivify/
• Google closure compiler http://code.google.com/closure/