All the open source projects I'm working on or the projects I've previously been working on can be found on my github. Most projects I started myself, some of them are forks or derivatives of existing projects. Here is a list of the things I consider noteworthy:
A CSS preprocessor as embedded Haskell.
First class composable record labels for Haskell.
Prototypes and proof of concepts
Use literate Haskell for HTML5 presentations.
Haskell OpenGL based 3d engine.
A generic approach to datatype persistency in Haskell.
Projects untouched for a while
Jailed IO monad. Run file based IO computations in restricted parts of the filesystem.
Modular Haskell HTTP server.
Wiki written in Haskell on top of Salvia.
Common Sub-Expression Elimination for graphs generated by the
Simple program to cut, select prefix/suffix of, reindex and shift SRT subtitle files.
Haskell list arrows.