gapt

gapt (Generic Architecture for Proofs), written in Scala, is intended to provide a framework and user-level tools for the input, analysis, transformation and visualization of formal proofs. In particular, the CERES system is being implemented using gapt.
Here's a screenshot of the proof viewer component of gapt:

Links: gapt framework, CERES system.

agito

agito, written in Java using Hibernate and Swing, is a program intended to simplify the administration of competitions in dog agility. At the moment, it is not publicly available.
Here's a screenshot of agito: