First there was Guy Kawasaki's 10/20/30 Rule of PowerPoint — 10 slides / 20 minutes long / no font smaller than 30 point.
Then, there is Pecha Kucha (Japanese word for "chatter") — 20 slides @ 20 seconds each.
Recently, I presented "Effectively Managing Your Board" to a group of school administrators using a Pecha Kucha approach to PowerPoint presentations. Both the group and I appreciated the change.
Here is author Dan Pink doing "Emotionally Intelligent Sinage" via Pecha Kucha. See what you think.