They’re all written in Media Center Markup Language, and do a pretty good job of bringing desktop-style applications to a 10-foot interface.

• Vista Media Center Mail lets you read email from a POP3 server, or you can read the contents of your Outlook inbox.
• Vista Media Center RSS Reader lets you, well I’ll let you guess what this one does.
• Vista Caller ID tells you when you’re receiving a phone call, and who it’s from. It also keeps a log of callers, and if you’ve got an entry for the caller in Outlook, a picture will even pop up on your TV.

http://www.pvrwire.com/2006/11/20/rss-called-id-and-email-for-vista-media-center/