The format of the PowerPoint Karaoke creation process was that everyone had 10 minutes to create and submit a slideshow to a centralized database. Then we randomized the speakers and PowerPoints and each gave a random 10 minute presentation on the slides.
This is a great version of Toastmasters which teaches how to give presentations on the fly. It is a fun and enjoyable practice that was first started in 2005 by a group of German artists. Now, the practice and experience of PowerPoint Karaoke is ubiquitous across many geek gatherings, and is increasingly a part of Unconference proceedings such as BarCamp and CyborgCamp (http://cyborgcamp.com).
PowerPoint Karaoke is often best played with a slightly inebriated group of 6-8 interesting people.
This is an example PowerPoint Karoke Presentation. This one does not have text, in order to increase the narrative flexibility of the speaker.
Use this deck of 66 slides with transitions between speakers to hold your own game of Powerpoint Karaoke! Best for a party with beer.