P6P is a decentralized public virtual network designed for traversing NAT. It's useful mainly for peer-to-peer applications that don't implement NAT traversal themselves. It uses an unrouted segment of IPv6 (Unique-local), so it doesn't collide with other networks. It does not implement any additional security.
Flush is a GTK+ BitTorrent client. It allows you to run many instances with different configurations for the same user, to create your own torrent files, and to set a custom download path for each file of the torrent. It also allows you to control a running instance from a command line interface: start/stop torrents, change download/upload rate limits, and change the maximum connections limit. Finished downloads can be automatically copied to a specified directory, and old torrents can be automatically removed.
Lince is a light and full featured BitTorrent client. The graphic interface has been designed to resemble the old Azureus, and is simple but powerful and gives the user all of the information in an easy and intuitive way. It is configurable and efficient, using as few resources as necessary.
Nephthys provides a Web interface to create file-sharing "buckets", through which data can be shared. Nephthys handles the buckets in the local filesystem of the server. Access and data transfer is made via FTP and WebDAV. Nephthys itself does not provide the access protocol, but relies on well known projects like Apache HTTPD (WebDAV) and ProFTPD (FTP).