Wikipedia
PowerPoint Karaoke, also known as Battledecks or Battle Decks, is an improvisational activity in which a participant must deliver a presentation based on a set of slides that they have never seen before. Its name is derived from Microsoft PowerPoint, the world's most popular presentation software, and karaoke, an activity in which a performer sings along with a pre-recorded backing track. The effect is intended to be comical, and PowerPoint Karaoke can be considered a form of improvisational theatre, or a type of Theatresports game.
The presentation can either be a real slideshow on an arcane topic, or a set of real slides from different presentations that are nonsensical when assembled together, or slides that are nonsensical on their own (in some cases created by randomly downloading images from the internet and adding unrelated text). In some cases, the presenter is given a theme beforehand that they must attempt to tie all the slides into.