Eric has a bunch of nice pages and research on Time Zone Problems. As far as I can tell, and fscinating as they are, they do not touch on our internal Hitchhiker Time which is closer to Astronomical Time.
I think we can call all the various human intracacies of time zone and date definitions as specified by archaic human institutions as Vogon Time. Of course everything is ultimately Vogon Time, but Some Vogons are Better Than Others.