there are a few apps out there for the mac that i've found through a good friend of mine, which i reckon are really, really good! they both come from the same group - http://www.lightheadsw.com - and both are very easy to run, and very convenient.

Caffeine allows you to disable the sleep function on your Mac for when you're watching a video or something, or simply don't want the fucker to go to sleep, and Papaya lets you drag-and-drop files to send to your friends without uploading - awesome for when you're in the middle of a piece and want to show everyone!