Apache Mahout's goal is to build scalable machine learning libraries. With scalable we mean:
Scalable to reasonably large data sets. Our core algorithms for clustering, classfication and batch based collaborative filtering are implemented on top of Apache Hadoop using the map/reduce paradigm. However we do not restrict contributions to Hadoop based implementations: Contributions that run on a single node or on a non-Hadoop cluster are welcome as well. The core libraries are highly optimized to allow for good performance also for non-distributed algorithms...

Honeytrap is a network security tool written to observe attacks against network services. As a low-interactive honeypot, it collects information regarding known or unknown network-based attacks and thus can provide early-warning information.

An extremely fast and lightweight file manager which features tabbed browsing and user-friendly interface.

FreeNAS enables users to build network-attached-storage (NAS) on nearly any hardware platform of their choosing.
Features: Replication, Data Protection, Encryption, Snapshots, File Sharing (CIFS, NFS, AFP, FTP, iSCSI, etc…), Web Interface, Plugins (Transmission, Firefly, MiniDLNA, etc…)....

Free Git Repository Management App,

HttpFox is an addon for Mozilla based browsers (Firefox, Flock, ...) that monitors and analyzes all incoming and outgoing HTTP traffic between the browser and the web servers.

It aims to bring the functionality known from tools like HttpWatch or IEInspector to the Firefox browser. ...

Bitcoin is a decentralized P2P electronic cash system without a central server or trusted parties. Users hold the crypto keys to their own money and transact directly with each other, with the help of the network to check for double-spending.

Openbravo is a fully functional integrated web-based open source ERP that is much more at a cost that is far less: be the true owner of your ERP and only pay for the professional support that you really need. The solution is designed for SMEs that are looking for an integrated way to manage their operations, optimize processes, increase customer satisfaction and ultimately increase profitability....

HTML Purifier is a standards-compliant HTML filter library written in PHP. HTML Purifier will not only remove all malicious code (better known as XSS) with a secure yet permissive whitelist, it will also make sure your documents are standards compliant, something only acheivable with a comprehensive knowledge of W3C's specifications....

YUI Javascript Documentation Tool,