Here's an interesting affect you can achieve using layers, and it doesn't really take a lot of time.I've posted one that i just did.You can achieve all kinds of effects just by playing with the hue/saturation layer, and the opacity of the individual layers.
The movie is in Quicktime format(.mov), so you'll need Quicktime installed to watch it.Use VLC, or Media Player Classic to view it, or whatever else you use to view a .mov.

Thanks J0nn0. I love video tutorials... and thats a nice effect.