For anyone using Google Calendar...

Have you been able to get it to remind you about calendar entries? I've put a couple things in my calendar just messing around and I cannot get the reminder function to work. I don't know if I actually have to be in Google Calendar before it will remind me, or if I can just be logged in to my Google Account and it will remind me or what?

I've got the Calendar widget on my Google Homepage and it would be great if it would remind me right out of the homepage screen with some kind of pop up, but it's not.