Well this is a funny post by Tim Sneath, and raise some question about who's in charge of naming products in Redmond :-)
So unless you're living on a desert island (and I doubt you can read this post anyway), you know about WPF/E being named SilverLight.
Thanks god, not the best name in the world, but it could have been worst :-)
Classic stuff, well my favourite in a typical Microsoft way (and I am surprised this didn't pick that one):
Microsoft Windows Presentation Foundation Live Rich Client ActiveX Player R2 Ultimate Edition Service Pack 1 CTP (or WPFLRCAPR2UESP1CTP for short)