drupe's missed call feature will notify you about missed calls with a little round bubble that'll appear on top of the home screen, in which your contact's avatar or initials will appear. If you get more than one missed call, the number of missed calls will be noted in the bubble.
You can tap it to open a mini drupe interface where you can select which action you'd like to initiate with the contact whose call you missed.
You can also drag the bubble to the bottom of the screen, where a pop up bar will appear. To dismiss the notification, drop it on the large X in the middle. In that bar you can also snooze the notification for an hour later, or simply return the call.