Proxy filesystem for FUSE is an implmentation of a filesystem that resolves symlinks and displays them as real folders as well as doing a few more things. For example, it is possible to point a folder or a single file at a file in the user's home directory. Also, it is possible to hide files and directories from the folder listing.
Debian packaging utilities for Truecrypt source helps to get Truecrypt running with a minimum of effort under Debian-based Linux systems (Debian and Ubuntu are officially supported). Truecrypt is an open source disk encryption software which uses a concept of containers to store encrypted data. The containers (or volumes) can be read transparently under Linux and Windows. The utilities create installable *.deb packages from the sources and those debs can be used in turn to install the encryption software.
Einarc is a unified storage RAID command line interface and an API that provides management for various hardware/software RAID devices, uniting them all in a single paradigm. Einarc works as a translator that makes it possible for a user to control all these devices using simple terms like "physical disc", "logical disc", "adapter", etc., while transparently converting these requests to proprietary RAID paradigms.
Tagsistant is a semantic filesystem for Linux and BSD kernels. It uses directories as tags and allows file tagging by simply putting files inside desired tag directories. The path you are walking by is your query, e.g. tagsistant/tag1/AND/tag2/OR/tag3/AND/tag2/. Being a low level interface, a filesystem can be instantly used by shell users, file managers, or CGI. A plug-in architecture is under development to add autotagging functionality for common files like .mp3, .ogg, .jpeg, .html, and .xml. A transparent ontology engine is also under development to allow users create a relationship schema between directories.
RheaVFS allows you to turn an archive into a virtual directory, so all files in the archive can be accessed as if they were in the virtual directory. This works transparently for all programs without any need to modify them. Currently there's read/write support for zip, tar.bz2/gz and gpg encrypted files.
Magma is an experimental network filesystem for Linux and BSD kernels based on a distributed hash table. Each object stored is called a "flare" and is managed using its SHA1 hash key. Flares can be moved as opaque objects from node to node and requests can be proxied through the network transparently to the user. Its goals are scalability, redundancy, data availability, compliance with POSIX, and basic encryption on the user side.