vvvv uses a visual programming interface. Therefore it provides a graphical programming language for easy prototyping and development.

vvvv is real time. where many other languages have distinct modes for building and running programs, vvvv only has one mode - runtime.

vvvv is free for non-commercial use, commercial use requires a license.

For a detailed overview of vvvvs features read the Propaganda or see some Screenshots of vvvv for a basic understanding of what you are dealing with here. People also seem to be interested in what the faq vvvv might mean.

The latest version is always available from the Downloads section.