I had no intention of suffering death by powerpoint, but I didn't say anything to address the problem. Instead I showed them several episodes of IGNITE speeches that I had in my iTunes. [To subscribe to Ignite speeches, you go into iTunes, choose "store" on the left hand side, and search "ignite podcast."] Miraculously, the next time we went down to the lab, they ALL deleted their silly bullet points and started making much nicer presentations.
The power of a good example: http://igniteshow.com/videos/blessed-are-cheesemakers
(I showed them Cheesemakers, Boiling water in 5 easy steps, and Cup noodles, among others.)