I noticed something by accident that actually turns out to be quite useful. I constantly use BugNET so maintaining a session is nice.
I first changed the session timeout config in web.config and under IIS. Check FAQ (http://bugnetproject.com/Documentation/tabid/57/topic/Frequently+Asked+Questions/Default.aspx)
Now using Firefox I subscribed to an RSS feed for a project within BugNET. So now, as long as I leave my browser open, my session will remain perpetual. This is becuase Firefox is sending requests in to get the RSS feed at regular intervals which is always ahead of the session timeout settings which I defined. This means the session will never expire. Quite usefull if you're not using Windows Authentication.