The first one was moving around some of the UI in ksnapshot (after chasing down an annoyance in kdelibs that would pop up a notification every time ksnapshot started if you had last saved a snapshot to a remote location). Here's the result of that "30 minute hack":
The default size is bigger (and it remembers the window size between restarts), the snapshot thumbnail has a bit of a shadow around it and the buttons have been re-arranged. Other than the window size saving, which I consider a bug fix, I'm not sure if the rest will make it into the next release or not. We'll see. I'm currently waiting for feedback from Rich Moore, my KSnapshot partner in crime. ;)
The second "30 minute hack" was inspired by finding a blog post I found linked to from Linux Today. One of the ideas behind making Plasma a flexible architecture is that people could not just talk but also do. When things are welded at the seams and full of internal assumptions, it can be hard to make changes. When things are loosely coupled and free of internal assumptions it is easy to make even radical changes. To prove this, I tasked myself with implementing this screenshot in half an hour:
Well, I "failed": it actually took me ~45 minutes to come up with this:
It has the arrows and dots, everything is clickable and works as described in the blog post and you get more or fewer dots when you add/remove virtual desktops. All of the elements are QGraphicsWidgets that belong to the Desktop containment and the arrows are drawn with an SVG from the standard Plasma Desktop Theme. Since they belong to the containment, they don't need to be set up, they aren't removable or movable, desktop widgets can freely overlap them and they show up on the widget dashboard (assuming dashboard-follows-desktop). I can imagine any number of nice improvements to it: some text saying which desktop you are on; on-hover animations for the circles; only reacting to clicks when they are on the circles, not just on the rects that bound the circles ...
You can find the diff against kdebase/workspace/plasma/desktop/containments/desktop here. Maybe someone will take that patch, fork the Desktop activity with it, spiffy it up a bit and release it with a new name on kde-apps.org. Personally, I'm not sure the idea of the arrows/dots on the desktop for virtual desktop switching is all that hot, but I wanted to show that not only are these kinds of things possible ... they are easy to do. That kind of flexibility doesn't happen by accident: we want people to experiment, try new things and re-shape Plasma apps in various ways. (An up-coming blog post about Plasma Classroom will touch on exactly this point.)
Now, if it took me 3/4ths of an hour to implement that, I can't imagine it taking someone with a little bit of Qt and/or KDE development experience more than a couple of hours to do the same thing. In fact, I bet many of you reading this could have achieved the same or better results in the same amount of time (maybe even less!) than it took me. So get hacking, people! :)