Calendar Events in Local Time
I may have come up with a work-around solution.
First step, you create the calendar entries which either take the current time zone setting of the desktop, the default time zone set in Evolution, or a time zone selected when creating the entries.
Next, you export the required entries to an *.ics file. In Evolution, select the calendar in question, right click and choose "Save As...". This can be facilitated if you put the entries you want to stay on local time in a separate calender, but it doesn't have to be that way.
Then you edit the *.ics file with an editor such as gedit. For those entries which should not change their local time entries when a different time zone in is use, modify the DTSTART (date time start) and DTEND (date time end) fields so as to remove the time zone information.
For example, suppose you have the following entry for an event:
change it to read as follows:
Notice carefully the semicolon comes immediately after the field label, but after the TZID field there is a colon then a space before the date and time information. When edited, the colon goes immediately after the field label and there is no space after the colon before the date and time information.
Finally, you re-import the *.ics file into Evolution, using File > Import ... and walk through the Evolution Import Assistant, selecting a single file and browsing to the modified file you have edited. Upon importing, since the events have a serial number the stored events already in the calendar are updated. Time zone information is removed (the Time Zone field is empty). Now, since the calendar has a time to start and a time to end the event, but no time zone information to apply offsets from UTC, it simply displays the event in local time.
I'm still testing this out but it seems to work so far.
If anyone knows any easier or better way to do this, I would love to hear it.