ruby update is a ruby script which helps people who install their packages from source keep their packages up to date. It does not attempt to install anything on its own, but simply scans your file system and lets you know if there is an updated version of a particular program. rupdate can only check the status of those programs for which it has been hard-coded to check.
GImageView is a GTK+ based image viewer. It supports tabbed browsing, thumbnail table views, directory tree views, drag and drop, reading the thumbnail cache of other famous image viewers, and a flexible user interface. It also support movies using the Xine library and MPlayer, and supports images in compressed archive formats like tar.gz, zip, and lha.
MaGnuX MP3 Control Server is a server that allows you to control the playing of MP3 songs. It uses mpg123 to play the songs, and features playlist management, a builtin Web server, IP-based access control, and much more. It's written entirely in Ruby, which makes it extremely flexible and very easy to extended.