This is something that I posted about on in Dutch on the IT and Education blog last week but I thought it was something that should be mentioned here also:
On Windows you can add Flash animations into a Powerpoint 2003/2007 presentation. So you could for example create a screencast demonstrating something, export that to SWF and add it to the presentation. Take it a step further and you can embed a FLV player (which in itself is available as SWF file) and have that play video downloaded from YouTube or other Flash video sites.
But not so in Powerpoint 2004 for Mac OS X. Even the workarounds that existed no longer work. And according to this post it isn’t going to be fixed for this version either.