Development on KDE 4, the next major version of the popular desktop environment, continues and if you're curious as to what progress is like, you might want to take a look at what is going on right now.
Thankfully, there is a Live Linux distribution containing a recent version of the (unstable) KDE 4 which you can download and try out if you want to have a play. The distribution is based on OpenSUSE and contains recent builds of KDE 4, KOffice and Amarok 2 from the Subversion repositories.
I did download this disc myself and boot it to give it a spin, but unfortunately I ran into a few problems and didn't have much success. Of course, that is the risk that you take with running pre-release software and it is probably an issue with my specfic hardware configuration, so your mileage may well vary and you will hopefully be able to get a little further than I did!
You can download an .iso image of the "KDE Four Live" CD from home.kde.org/~binner/kde-four-live/, which you can then burn to disc.