Hi, I had the same problem with my Samsung Galaxy Note II, after you make sure that you are using the default calender, I found out that if I changed the "Lock time zone" option in the calender settings, the alert will go off, and of course in "Event notification" you need to make sure that "Set alerts & notifications" is set to "Alert" not "status bar notification" or "Off", one more thing, I used to use "google calender" and sometimes it is not going off (maybe because it is not syncing properly) , but when I used "My Calender" it worked fine. So it is about the timing option in calender settings.