makeself is a small shell script that generates a self-extractable compressed TAR archive from a directory. The resulting file appears as a shell script, and can be launched as is. The archive will then uncompress itself to a temporary directory and an arbitrary command will be executed (for example, an installation script). This is pretty similar to archives generated with WinZip Self-Extractor in the Windows world.
The GNOME Structured File Library is a utility library for reading and writing structured file formats. Support for MS OLE2 streams is complete, as is zip import. There is also support for document metadata and some initial work on decompressing VBA streams in OLE files for future conversion to other languages. This library replaces libole2 and is used in gnumeric, mrproject, abiword, libwv2, koffice. It is also part of the AAF format.
bdmn is client/server-oriented backup system. The daemon runs on the machine being backed up, and the client runs on the machine that stores the backup. It is very simple, but very fast. It only uses tar, gzip, uuencode, and Perl, so it is portable to many operating systems. It includes a very simple access control system for itself.