Do the simplest thing that could possibly work: http://www.grayman.de/gregor-rayman_en.php4
(I will refactor this homepage later)
A warm welcome to this wiki!
Have you tried MathQuizOne?
If you are bored, have a look at a some simple games in JavaScript: http://www.grayman.de/four-wins-3d_en-php4
If you want to test your knowledge about JavaGenerics, have a look at http://www.grayman.de/quiz/java-generics-en.quiz (and I'd be happy if you helped me to correct the typing errors. :-)