Reminders is either one of the most useful apps in OS X 10.8 or one of the most annoying, depending on who you talk to. I use Reminders on my iPhone a lot, but not so much on my Mac. Part of the reason is because I assumed that once a Reminder notification popped up on screen my only options were to leave it there, close it (thus disabling the reminder for good) or "snooze" it. But there's actually a hidden option I never knew about.
As Lex Friedman points out in a new OS X tips video over on Macworld, you can actually click and hold on a Reminder notification and then flick it off to the side of the screen. Doing this will tell the reminder to reappear in 10 minutes' time. It's a great option when you want to clear a reminder from your screen -- say, to access a window the the desktop underneath -- but don't want to totally forget about the Reminder.
Lex shares several other Reminder tips in his video, so be sure to check it out.