I'm a software developer at the Guardian (http://www.guardian.co.uk/profile/roberto-tyley) - these are a couple of projects I work on in my spare time:

http://code.google.com/p/glug/ - log visualizer for multi-threaded systems

https://sharesource.org/project/sasa/ - Java port of the DIERCKX (also known as FITPACK) library of Fortran subroutines for calculating smoothing splines for various kinds of data.