At my job/co-op I am in charge of redesigning their custom Facebook tab. The one they currently have is outdated.
After researching a lot to find what other companies were doing on Facebook and researching other web trends, we found Parallax scrolling, which is essentially multiple layer backgrounds moving at different speeds to give the illusion of depth.
An earphone (headphones) company called Yurbuds has an Awesome site utilizing parallax scrolling: http://www.yurbuds.com/
Basically for the Facebook page we are creating, we are going to do something similar, but for our products and on Facebook. I have yet to see it take place on Facebook, but we’ve done some small testing and it looks like it’ll work and be pretty awesome.