Frank (and quite a few other people) recently linked to this little experiment implemented in Flash to see how well people would go using an interface that not only didn’t need mouse clicks but actively discouraged it. I had seen an earlier version of the site a while ago but visited again and was interested to see what they had done. I was playing with some of the guesture buttons and thought that they would be relatively easy to implement in WPF (relative to what?). I did some playing and I was able to implement the hover guesture button to a certain degree using Blend although more code will be required to make it work exactly like the one in the demonstration.
One of the challenges I had was editing the control template and getting the centering of the <ContentPresenter /> to work if I wrapped it in a Canvas (which is what I was using for the wipe effect).