Just wanted to share some experience I've had recently with doing some lunch and learn sessions on the Raspberry Pi.
So, first, if there has never been a lunch and learn where you currently work (business, school, whatever), do one. You'll be surprised at the response. And, no, the lunch is not what attracts people, these are bring your own lunch session.
Second, don't cover too much material. Perhaps have one that is "Intro to Raspberry Pi". Spend a few minutes talking about where the Pi came from, and then show the individual components. Make sure you'll have a keyboard, mouse and monitor that work with the Pi.
Third, answer questions as they come, but don't spend too much time on details. Keep an eye on your time. Else, you'll get questions on GPIOs that can take hours to explain... Refer the audience to this forum for details.
Fourth, show how to image an OS to an SD card. dd takes only about 2:30 minutes for the current Raspbian image on a modern sd or microsd (20MB/s). Offer to help attendees if they get into an issue where their card does not boot their Raspberry Pi.
Fifth, boot the new card, show a few command line things, startx and show the desktop and apps.
Sixth, conclude the intro session by letting people come and play with the Raspberry Pi. Ideally, for large groups, you'll want more than one. It's more work, but worth it.
I'll be doing my 12th "intro" lunch and learn next week (at a University). I'll be starting some lunch and "workshop" sessions soon, and I'll contribute some more notes.
http://raspberry-python.blogspot.com - http://www.3DFutureTech.info - @f_dion