A long time ago, I wrote a piece about how I didn't like kcalc. It contained a very lame pyqt script showing a (IMHO) nicer calculator. Strangely, that lead to two very cool implementations of the concept!
One of them was written in Ruby, the other one in C++. I think that has some potential.
A few months later, I wrote a spreadsheet based on the same concept. Also based on PyQt.
This StupidSheet has some conceptual problems. Like, if you want to import Excel sheets, you would have to rewrite basic in python, so it's not a practical program, but it is a rather nice example showing programming using dynamic languages.
In fact, I used it as such last week at CafeConf.
Now, here's the challenge. If people that know how to write Ruby or Java apps using Qt (or KDE, why not) could write a similar application, we all could write a comparative guide to Qt/KDE programming on different languages.
Since we would all be starting with a not-too-complex, but really non-trivial example, and we would all do the same one, it should be pretty unbiased.
In fact, if you think this example is biased, please propose another one, and do this thing anyway.
You can find StupidSheet here
It has some small bugs (try setting B1 to A1+1 with no value in A1 ;-) but they are easy to fix.
We could remove some features (like the weird pasting stuff) to make the example more didactic.
I hope this gets some answers :-)