A package corresponding to TIP 245 that gives you the amount of time a user has been inactive.
davidw - I packaged up the code I found in the TIP proposal patch and have put it at http://www.dedasys.com/freesoftware/files/ (look for tkinactive). It's in an initial "it works for me" state, but could probably use more fixing, and could certainly use someone with MacOS X expertise to add that bit back in (I don't have a Mac system to do the work on). Currently supports Linux and Windows (with some manual build steps).
Works like so:
tkinactive ?-displayof window? ?reset?
and returns the inactive time in milliseconds.
kostix (on 2008-01-12) adds: Also see tk inactive for built-in support in Tk 8.5. For older versions of Tk in X you may check tkXwin.