Many people have been complaining about the fact that unregistered users see all times on the board in GMT, despite what is set in the Control Panel. In order for timezoneoffset to work, the user has to have a timezone offset specified in their profile. I wanted to fix this on my board, and thought I'd share what I did.
In sessions.php, all you have to do is modify the timezone offset for guests. On line 285, find where it says:
PHP Code:
$bbuserinfo['timezoneoffset']=0;
and change that to whatever you'd like the default time to be. For example, I have:
PHP Code:
$bbuserinfo['timezoneoffset']=-5;
The only thing that this doesn't do is change the part of the board that says "All times are GMT..." - but at least where it says "Time Now:" will be correct, and not 5 hours ahead of 99.99% of my visitors.
Just thought I'd share

.
-jim