Powerpoint - Installed on all UAGC computers, Powerpoint is the classic presentation tool. Though lacking in flair, Powerpoints can efficiently display text, images, videos, etc. at the click of a button -- and you can add automatic timers and audio for a slideshow presentation that runs on its own.
Screen Cast-o-matic - Record videos of your computer screen. No audio available (unless you pay), but you can present audio while you play the video or record the audio separately and try to play both files at once.