Before that preview of the romantic comedy that makes your teeth ache from saccharine overload, you might see a 30-second spot that begins with the buzz of mosquitoes.

A question, “A mosquito bite … nuisance or death sentence?” appears on the screen, and then viewers quickly learn the answer. More than 2,000 children die each day from malaria after being bitten by an infected mosquito.

The video, shown below, is part of a campaign by World Vision to build awareness about malaria and how to stop it. The trailer will be playing in select theaters in nine cities this summer.

Action Against Hunger offers a very different twist on the movie-trailer as awareness-raising technique with its online video “No Hunger.”

The video starts with the standard movie-trailer opener: “The following preview has been approved for all audiences.” The clip then shows aid workers who speak about the consequences of hunger as images of malnourished children appear on the screen.

Viewers are told that the earth produces enough food for twice its population and that $55 can provide enough nutrients to save the life of a malnourished child. Yet 5 million children die each year from severe malnutrition.

The video cuts to production information: “From the director who mobilized humanity against climate change,” reads the screen. “An Oscar winner and Nobel Laureate, Al Gore.”

But it turns out that the trailer isn’t a preview for a film at all — but part of a campaign to raise awareness about hunger and convince Mr. Gore to make such a film.

More than 65,000 people, many of them in Europe where Action Against Hunger’s affiliates have already begun the campaign, have signed a petition asking Mr. Gore to create the film. The charity hopes to get at least 250,000 signatures and present the petition to Mr. Gore in December.

The charity also hopes to raise money with the video, although it doesn’t have a specific fund-raising goal. People who watch the trailer are directed to ways they can give.

Action Against Hunger sent a letter to Mr. Gore before beginning the campaign.

While the video is currently available only online, charity officials say they have made headway in getting it shown in theaters as well.

What do you think of these campaigns? Click on the comments box below to share your thoughts.