As part of another project I am developing ensure4j. The syntax (see the examples here) is working quite nicely, ensure4j is already very useful for internal use.
Lately I was busy adding tests that are able to verify if some code (e.g. an optimizer that uses random, like genetic algorithm, simulated annealing, …) produces the desired [...]

On my quest of successfully installing a wiki at my workplace, I came to the conclusion that the biggest problem is a social one. On this quest, I fought with Google and other search engines to present you this list of great links to this topic:

Getting Your Wiki Adpoted
It’s On The Wiki!
HOWTO Install TWiki as [...]

Subversion has the ability to output a log file in XML format. I think it would be pretty straightforward to implement an application in Ruby (mabe with use of Amrita), that creates some nice looking statistic about the repository.
On a side note, I have a personal subversion repository that contains everything I have accomplished [...]

SuperMemo is the only application I know of that tries to improve ones memory. The problem is that it is not free, and only works in Windows.
The idea is to write an application similar to supermemo called donofo (= do not forget), but written in a platform independent language (Ruby or XUL), and with mathematical [...]

Python has a quite interesting programming challenge. Unfortunately it is not possible to do the challenge in any other programming language, because in the later levels it starts to depend on special libraries that are only available in Python.
The idea is to create a similar challenge that does not depend on a programming language. Ruby [...]