From what I have found with the pproxy program since I run my own, they all turn over at the same time - 0:00 GMT (or UTC). Since Russ is hosting the Borg's pproxy if I'm not mistaken and he's in the Seattle area which is on PDT, then midnite UTC is 17:00 hrs PDT (or 5pm). Dennis - not sure where in Canada you are but it would be 6pm MDT, 7pm CDT or 8pm EDT.
The pproxy is configurable to flush after receiving so many blocks but I'm looking for a way myself to maybe have it flush whatever it has just before the turnover. I haven't delved enough into the docs to determine whether there's a commandline parameter like the client, that will tell it to -flush (and then that could be setup as a Task in windoze or cron job in *nix), but my initial read-through didn't find anything. I know the pproxy can be restarted without shutting it down via a <CTL><BREAK> and that will flush it too, but other than that, I'm at a loss.