HexChat is an IRC client for Ubuntu. It comes with all the features you might expect from a chat client such as tabbed interface, auto-connect, theme support …
PhotoFiltreLX is a lightweight image editing software for Linux. It lets you apply cool effects to your photos using a huge collection of filters.
Mundus is a simple application that allows you to delete the configuration files of uninstalled application, and thus keeping your home folder clean.
Picard is an audio tagger written in Python. It grabs metadata from MusicBrainz allowing you to easily tag your albums.
ffDiaporama is a Qt application that lets you easily create video slideshows from various sources such as photos, music, text and movie clips.