Quick idea: I noticed that recently the time a thread was edited last, shows behind the threads subject at different locations throughout the site - also the time a post was posted shows behind the subject of that post:

AO Wargame posted: 01-27-2002 02:48 AM

Maybe, instead of date it was posted, the time elapsed after that date could be shown, like this:

AO Wargame posted 1 day, 4 hours and 5 minutes ago.

After all, that's what you want to know anyway: "How old is this, how long ago was this posted?" Furhermore, you eliminate using zone-bound time.