Mashed potato - instructional video here
http://www.youtube.com/watch?v=nzGPpPUML94. Also see the movie "Hairspray".
Lindy hop - Good if you have a fun-loving partner and can edit an electro swing song into your video.
Funky chicken - There's a guy named mahalodotcommahalodotcom on YouTube that has a whole bunch of how-to videos for various dances.
Electric slide - If you can arrange a bunch of people to do it somewhere public like in the Wal-Mart.
Additionally, you might want to switch up your masks, rather than just wearing the Jason mask all the time.