Comedic moments may be caught by just having a camera rolling tape at the right place and the right time such as Mark Lewis' documentary "Lord of the Gourds," about extreme gardeners competing for the world's largest pumpkin. Film a subject who is preparing to compete in a local fair, including everyday routine and any preparation for the competition. The locals, the other competitors, and the county fair atmosphere are all opportunities for spontaneous humor as your camera is rolling at the right place and the right time.
Morgan Spurlock's "Super Size Me" is about his personal quest to exploit the consequences of eating only fast food for 30 days. The results are informative, somewhat alarming, and entertaining. Tape someone who decides to abandon his car for a month and walks, rides a bus, rides a bike, or taxis everywhere they go. Film the adventures of the journey to and from each day including the people at bus stops, the bike ride and the close mishaps that happen. The results of not driving, such as improved physical shape, less toxins in the air and cost savings are the types of messages a documentary as this might exploit.
Michael Moore's "Roger and Me" is an example of the "gotcha" documentary. Mr. Moore exposes a large automotive company that closed manufacturing plants in order to outsource. During a great portion of the documentary Moore tries to land an interview with General Motors CEO Roger Smith, and gets some great candid moments in the process. This type of humor comes in the form of irony and to create your own funny documentary of this type could be as simple as keeping up with your local politics. News stations expose politicians from time to time. Expand a news story with some investigating of your own while the camera is rolling.
Luc Jacquet's "March of the Penguins" is an example of using the narrator's voice to tell a story, although the original version had the penguins as narrator. This documentary is informative about the life of penguins while being entertaining through the use of witty narrator comments and adding music in the editing. Using animals, or objects and giving them voice opens up endless possibilities, particularly if it is informative and entertaining at the same time.