In three words, http://www.cuckoosandbox.org is a malware analysis system.
What does that mean? It simply means that you can throw any suspicious file at it and in a matter of seconds Cuckoo will provide you back some detailed results outlining what such file did when executed inside an isolated environment.
If you want to contribute to development, please read http://www.cuckoosandbox.org/development.html and http://www.cuckoofoundation.org/contribute.html first. Make sure you check our Issues and Pull Requests and that you join our IRC channel.
This is a development version, we do not recommend its use in production.
You can find a full documentation of the latest stable release http://docs.cuckoosandbox.org.