What developer technologies are you experimenting with?

I'm curious to hear which developer technologies (both from Microsoft and everyone else) you've checked out recently. 

As you can see from my blog, I spent a good bit of time last month playing with XNA and was very impressed.  I've recently been splitting time between the Windows Live services (Local, Messenger, Activities), and some of what's new in Visual Studio "Orcas" - particularly Linq.

But it's a full-time job keeping up with everything that's new.  For instance, I still haven't done a project with the Expression Blend release candidate, and it looks like the new samples are dazzling.  And there are lots of web technologies (Ruby, etc., WPF/E, and countless others) that are getting a lot of buzz, and I haven't had a chance to play with all of them myself.

So I'd love to hear what you've been exploring yourself, and what your impressions were.