Auto-update linked spreadsheets or other information
PowerPoint can automatically update your presentation with new information from linked files whenever the linked files change.
But it only updates when you close and reopen the presentation. What if you have a file that you change during a presentation? How can you get it to update automatically?
There are ways of forcing updates with VBA/macros, but you'd have to trigger those somehow from within the show or write some very complex code to make the update happen automatically when a file changes.
Or you might be able to work out a very tricky linking trick that bounces between several files (containing the same presentation), forcing the part that contains the linked content to open whenever you come to it. The thought of it makes my head hurt.
If you have a budget to work with, have a look at DataPoint from PresentationPoint.
It will automatically update your presentation with information from spreadsheets, text and other file types. Live. During a show.