Sometimes I wanted to look at a previous conversation, and so I looked up how to see the Live Messenger history. I found an option to save message logs in an xml format. I could view these logs in IE, but I wanted a better interface that would separate by username, and have better search capabilities.
So, I put together a quick app in Windows Forms. It doesn't do much; the main interest for me was to use the XmlTextReader (a very nice lightweight xml reader built in to .NET, perfect for this task). I was also interested in RTF; I wrote code to translate the formatting into raw RTF to pass to the RichTextBox control. .NET is great for putting together a little program like this.
Source code, released under the GPLv3. (You'll need the .NET 2.0 framework).