There is a whole series of videos by a guy named Jack Vale. He invented a hand held fart machine (kind of like a mini whoopi cushion that doesn't have to be blown up) and used the videos to get people to buy it.
[youtube]http://www.youtube.com/watch?v=9pZsJXM9m3I[/youtube]
[youtube]http://www.youtube.com/watch?v=XdiF3LzHz_I[/youtube]
[youtube]http://www.youtube.com/watch?v=ClLtvPgaFKM[/youtube]
[youtube]http://www.youtube.com/watch?v=7NIWw91LIM4[/youtube]