I’ve made several posts linking to humorous or unusual fan-made recuts of movie trailers. The Wikipedia entry “Re-cut trailers” is a pretty authoritative reference that includes links to most of them:
Re-cut trailers refers to a re-edited film trailer that is created by re-editing footage from that film, or possibly just from that film’s trailer. Re-cut trailers have become a popular internet phenomenon since fall of 2005. In almost all cases, these re-cut trailers derive their humor from casting the film’s plot in a different light- these fake trailers present the film as something that it is very much not. For instance, a film with a murderous plot is made to look like a light and happy film, or vice versa.