Ever play presentation karaoke? It's something I played for the first time at Agile 2014.
Basically you take a hat and fill it full of slips of paper describing topics of presentations the audience should know. For our group, it was stuff like "self-directed work teams" or "TDD"
You draw a topic and come to the front of the room. For the next five minutes or so, you talk on your topic. The trick is that in the background there is a presentation deck playing odd and strange slides that advance every 15-30 seconds or so. Give your presentation however you like -- but you have to speak as if this were your deck and the slides are supporting what you're saying.
It's a great way to practice thinking on your feet. Also fun for extroverts and folks who use slide decks a lot.
I enjoyed it so much I went home and wrote a 1-day app. It's not very complex and there's not many bells and whistles, but it works! And several times over the last year I've found myself bringing up the app and showing it to folks.
There's a lean startup/MVP discussion here as well You can get a lot of value out of a very small amount of work if you structure your execution carefully.
In case you're interested, here's the site: http://presentation-karaoke.com/