X Persistent Remote Applications (xpra) is "screen for X". It lets you run applications remotely (like ordinary X or VNC), but unlike ordinary X, these applications are "persistent" if you lose your connection, or even if you want to switch to another computer. Also unlike VNC, they are ordinary applications on your desktop managed by your window manager, not trapped in a box.
Envoy is an "open and display things" library. It provides an interface for storing file associations and launching files based on those associations. This comes with a wrapper program to enable desktop users to benefit from the file associations without developers adding explicit support. It also supports opening any URI transparently, as long as the corresponding protocol support exists: applications that want simple read (and write, depending on the protocol) access to files, wherever they are, can use the envoy API to do so.
Javeau is a small tool meant to provide an easy way to create and use encrypted directories, using strong cryptography and a simple interface. It works under Java 6. Data stored in these folders are encrypted and safe (using 256 bit encryption); they can be accessed only by the user (by providing the password used to create the folder), and their integrity is checked to prevent data tampering. The application sports a convenient file-manager-like interface, is very fast and small, and is completely cross-platform: you can access your encrypted storage everywhere you can run a Java 6 VM.