So I was playing around on youtube and found many trailers that were made by fans. They have reedited horror films to look like comedies, and comedies to look like horror films and many to others to look like films depicting gay love a la Brokeback Mountain.
Here are a few of the good ones that I found, but there are too many to list here. It is especially amazing how much mood and tone music gives to film. I remember when I was a kid and I watched a horror movie, my mom would always turn off the sound and it would no longer be scary. Try it sometime, it's amazing how well it works. But I'm digressing. Here are some fun links: