Ahhh.... the allure of the marshmallow shooter... I know it captivated my young Maker Faire attendees last spring... I know adult family members who send marshmallow launcher kits, right along with RC helicopters, model rockets, circuit kits, and solar-powered electronics projects. As this video from President Obama's tour of winning Google Science Fair projects shows, there's something innate to the seemingly timeless fascination with what happens when you combine air pressure, marshmallows, and a series of tubing.
For a look back at our quasi-retrospective on Maker Faire (and our questions about the "germs" that might live in an old-fashioned, blow-style, marshmallow shooter), see: Blow: From Marshmallows to Microbes.