ideone.com : Ideone is an online compiler and debugging tool which allows youto compile source code and execute it online in more than 60 programming languages.
repl.it : Powerful and simple online compiler, IDE, interpreter, and REPL. Code, compile, and run code in 30+ programming languages. including JavaScript, Pytho...
Query Mongo : Convert MySQL Queries to MongoDB Syntax
RoundPic : Online tool for making anti-aliased rounded corners (very Web 2.0!) for avatars and images
rsizr : rsizr is a Flash application that lets you resize JPG, PNG, and GIF images on your computer. With rsizr, in addition to normal image rescaling and cro...