Windows Live Messenger Beta Invite for WPF Sample Suggestion: wanna trade?

I have one Messenger Beta invite to give out and I'm always looking for WPF sample suggestions. So...

I have no strict criteria. The first suggestion that makes me think "hmm, that looks interesting" wins. Tips: if it's trivially simple or insanely complicated, you probably won't get it. Take a look at the samples I've already posted as examples. I'd love to see an example of a useful control that isn't "in the box".

Send me the passport/messenger/hotmail address that you want to use. (This will be the *only* address you can sign-in to the beta with.)

I reserve the right to share all entries with people on my team or the public at large.

Use the Contact link, not comments (unless you want everyone in the world to know your email address.)

Winner will be notified via email. Everyone else: please don't send me a "did you pick someone yet?" email. I'll update this post when we have a winner.