Sleep No More is a tiny menu bar application, that allows you to prevent your Mac from sleeping for a specified amount of time. An app like this is perfect for those who like to watch movies on the computer but still keep their sleep settings set to a low amount (I keep mine at 15 minutes to conserve battery life on my MacBook Air).
Sleep No More allows you to prevent computer sleep, display sleep or both of them simultaneously. Unlike other sleep-prevention apps, Sleep No More can be set to prevent sleep for up to 24-hours. That makes it perfect for preventing your Mac from sleeping while downloading massive files over the Net.
The interface is pretty slick, using an analog dial as the method for setting the time. You simply click and drag to set the time. The app even makes a nice clicking sound as you drag.
Sleep No More is free, and available only in the Mac App Store.