Hello, I was watching TCM last night and they showed a movie, An American Hippie In Israel, that would be perfect for Rifftrax. The movie was made in the early 70s and is funny without the riffing. Scenes includes 4 hippies surviving a mass shooting with nothing but smiles and laughter within minutes of the massacre, driving around in a circle and a dream sequence about man vs. machine that makes the viewers root for the machines.

Here is the Wikipedia entry for the movie: http://en.wikipedia.org/wiki/An_American_Hippie_in_Israel

Have fun with it and thanks for all the laughter!