What time is it?

I registered for an online 'webinar' today. The confirmation e-mail informed me the event would take place on the specified date at 15:00 BST, 16:00 CEST. Not being sure how to translate this to U.S. time zones, I had to do a search on those terms to find out what they meant. In the process I found a good site at www.computerhope.com/jargon/t/time.htm with a list of several time zone abbreviations and their relationship to GMT. BST in this case is British Summer Time, and CEST is Central Europe Summer Time.