When you develop a language binding you never know what sort of thing people will develop with them, and it's really fun when people turn up with something. Yesterday I was chatting with Tobias Kappe on irc and he mentioned his Selene project that allows you to create dialogs in C# that are toolkit independent.
Tobias said that he was learning the Qt api, and the project uses the GTK as an alternative toolkit. Here is an example of how you can combine both in a single source file:
I've always liked learning new stuff such as toolkits and languages, and so this project is right up my street. You can learn C# programming in both Qyoto Qt and GTK# and see how they compare. Then maybe try a third variant with KDE widgets using Kimono. Once you are using the KDE classes, you can have a look at KConfig that does something similar, and try it out and see if you can borrow some ideas.
By the time you've done all that you've covered a lot of ground, although each individual step is easy and fun. That's what lowering the barrier to entry to Qt/KDE programming is all about, and a good demonstration of how language bindings can help. Some people may be able to learn C++, pick up the Qt and KDE apis and write a large app straightaway. But for a lot of people that is just too much to achieve in one go, and if you wanted an easier way to get going, I think helping out Tobias with the Selene project could be ideal.