Dan -
I just a presentation last week at our local LUG and here's what I did. (And for reference, this is the first time in almost 2 years I've had Linux and Wine loaded on my laptop - I like what you guys did with the place.)
1. I gave the presentation in Powerpoint 2003 and CrossOver Office. I started the presentation on a separate desktop before anyone saw me do it, so they didn't know it was Powerpoint. At the appropriate time during the presentation for eye candy, I pressed ESC and said - "And here's Powerpoint". I also pointed out that it runs so stunningly well that's it's completely unimpressive.. and that's exactly what Wine should be. I also started up Word quickly to show it running.
2. Oh, all of these demos were shortcuts on my desktop so I could start them quickly.
3. I ran Wine's iexplore.exe and let it load winehq.org. Then I explained some architecture stuff like how it was a Wine MSHTML.DLL connecting to a Windows Gecko engine for rendering. It was also a brief intro intro into what a Winelib app was.
4. Then I VERY briefly showed off Wine's regedit, mostly as an intro for folks to understand Wine has a registry.
5. Finally, I ran 3DMark2001SE to show off 3D. I wish I could have gotten 3DMark05 or 06 running, and I suspect I could have with some prodding, but they do seem to require a software purchase and license key to do anything cool. At least 01 is D3D8 and there's good demo's that don't require a license key. 01 does have some good eye candy - I let the demos run for about 10 minutes while I used a whiteboard to illustrate some architecture stuff with Wine. Note: if you run 3D demos on a projector you might want to consider using desktop mode. I got lucky and the projector was ok with the resolution resizing and it only had a bit of a glitch. I do suspect a lot of projectors will be unhappy with Wine changing resolutions.
I considered showing off a real game, like WoW or Call of Duty, but the real problem was the sheer size of the downloads - 600MB and the install size, 16GB, which my little laptop just wasn't up for since I was putting the 3D demo together at the last minute. Also, I wanted something that would run automatically that I didn't have to interact with, hence the 3DMark01 demo.
6. You might want to consider showing off Google's Picasa and it's custom Wine implementation. I almost did.. and you'd know even more about the guts of that.
-Brian