Toolduino is a simple software tool that lets you easily interact with Arduino hardware. With this software you can easily can test the circuits you create. The Arduino must be running the Firmata firmware that comes with the Arduino IDE. Things can’t get much easier for all kinds of hacks. You can just connect some components to Arduino board and then use the intuitive user interface (for those into electronics) for controlling the I/O pins on the board. I can recommend this software for everybody starting to hack with Arduino boards.
Toolduino is available for Windows, Mac OS X, and Linux. Toolduino is a Java application (because Processing is really Java under the covers), so you need to have a Java runtime environment (JRE) installed on your computer. I tested the software on Windows and it seemed to work well on it.