I've been messing around with the Gradient Map effect. Like, making a duplicate layer of a clip, changing the bottom layer to grayscale, then masking the character on the top layer and turning them purple or something
It takes a while though, since I do all my masking in Wax, rendering the clip with a green screen, then importing into Vegas and chroma-keying out the background
I've also been experimenting with borders and stuff. Like lowering the saturation, and using the Cookie Cutter to make it transparent round the edges, then putting a grunge backround or something behind it.