Have you seen Flotzam? It's a fun mash-up that Karsten and Tim put together that aggregates a bunch of different data sources: Twitter, Facebook, Flickr, Digg, YouTube and indeed any general RSS feed. You can install it either as an application or a screen saver, and it's a nice way to see what's going on out there on the "tubes". Karsten has coined the term panopticon to describe it (from the Greek, meaning all seeing); to me, this feels like it has the potential to form the first step of a project to build the ultimate, pluggable, modular social networking client.
Being a WPF application, Flotzam can be easily restyled. From the enter/exit transitions for new items to the overall visual look and feel of the Flotzam interface, you can do almost anything you want just by tweaking the XAML mark-up. And with MIX08 selling out quickly (hope you've registered), the team thought it would be fun to put together a little contest that gives you the chance to experiment with WPF by creating your own custom themes. We'll use the best entries at MIX, both on the keynote screens and on all the PCs around the show; Karsten hopes that walking around the show will be like visiting some kind of art installation with all these different skins appearing.
Entering the contest is easy: everything you need to know can be found on the visitmix site. We've even got screencasts available to show you exactly how to use Blend to do the customization. Let your inner artist out - show us what you're capable of!