Jseki is a collection of utilities basically a repository for any Open-Source Go-related programming of RossWerner.
home page: http://sourceforge.net/projects/jseki
Currently It exist to two applications which you might find of use:
http://jseki.sourceforge.net/Tsumego/ a program that utilizes spaced repetition ( the Leitner method) to help memorize life-and-death problems. It uses the "Status?" approach rather than requiring the user to find the correct move, which more closely approximates real-game scenarios that a player is likely to encounter.
I have tinkered with the code of it and repaired some flaws (that cost me several hours). Find the repaired program and code "version 0.5.1":
https://sourceforge.net/projects/mygogrinder/files/ - I put it there until Ross gives it another place. RueLue
http://jseki.sourceforge.net/KgsStatistics This tool downloads all your games from KGS, shows some statistics like win/loss percentage, and has a simple "Joseki Reviewer" where you can see how your openings compare against a simple Joseki dictionary, possibly alerting you to weaknesses in your opening (or in your opponents' openings).
http://jseki.sourceforge.net/PairPro/ PairPro is a program to assist tournament directors? in the pairing? process, as well as reporting the results of the tournament (e.g. to the AGA). It can also be used by people who are running a school club or the like who just want to record the results of games played and calculate relative strengths of the players.
Currently PairPro is in proof-of-concept stage. The above link has some hand-drawn mockups of what the application should look like, and some descriptions of how the application is meant to be used. All the UI screens found in those mockups have been implemented in Java code, but only a handful of them actually do anything useful.