I was asked once to do this. Here was my answer:
No
In theory, as leo has suggested, it COULD be done, but to do so would be so intensive on server resources... oh, it just gives me chills.
Think about the processing power you would eat up by running a clock (iteration) on every single logged in user that was on your site. And keeping up with when pages are served to what session and resetting if needed, etc... OUCH!
If anyone could come up with an idea on how to do it efficiently, then I would love to hear it (actually, my client would), but I gave it some thought, looked at a few different ways including checking the existence of the sessionID every so many seconds on the pages themselves, and then redirecting the second it wasn't there anymore (not real-time, but close), but the best I could tell, that would take remote scripting (which I have no experience with) combined a constantly running javascript function using setTimeout() -- which is not as intensive on the server, but more so on the client... I just don't see it happening. Moreover, I have not ever seen a site that did it...
Anyone?