With the current state of film technology, it is possible for people to create short films fairly inexpensively. These methods can also be used to create trailers for films that have not been made yet, but the trailers can be used to gather funding for the full-length film.
Here is an example of a such a potential movie, a film that explores nerd culture in a new way. I hope that this interesting trailer can elicit enough money in order for the project to go through.