I am in the Pacific timezone. My portal, calendar, and user profiles are all set to the Pacific (-480) timezone. Switching that to -420 in timezones.xml caused all kinds of problems, including the calendar displaying different times (one hour off) in the tooltips vs. what was shown in the event details. Very strange behavior.

While I agree this really should be fixed in the core, it looks like that isn't going to happen anytime soon. I think implementing a fix in the Events module is the way to go. It sounds like your idea of the three additional DST settings would work wonderfully, even if the start and end dates/times for DST changed again. The added bonus is that it could be implemented right now and then simply not used if/when the core gets their stuff together.

Roger, my intent with the proposed change is NOT to display the Events in the User's Time/Zone.  We tried going down this route and it created way too much confusion.  The way the module now works is the Admin selects a TimeZone for ALL Events in the instance.  This TZ can be optionally displayed on the pages (version 3.3.8).  So, now the only problem we have is getting the DST Offset correct for the selected TimeZone.

Well it looks like I've tracked down my forum and users online problem. It looks like the SQL Server time is wrong, and the getdate() function in a stored procedure uses SQL Server time, which is what both Users Online and Forum use to set the creation date. Now to get the hosting company to correct it.....

However, not sure this helps anyone else, but certainly is a factor to think of.

Roger