On the Non-Photorealistic Rendering front, I've developed a new technique to make the computer spit out what appears to be organic hand-drawn illustrations. For still frames, I've seen nothing close to these results. But making it animate is going to take a little work. Still, once that's accomplished, I believe I can rebuild this as a generic video filter. Might be worth doing.
And in Stereoscopic Imaging, I can finally convert standard photographs into 3D views, complete with all the rounded surfaces most artists in the field leave out. That's something I was struggling to accomplish a few years back, but eventually put aside to wait for computers to get faster. As it happens, this would have been worked even then. The process is very simple, and can be performed in Photoshop without any outside plugins.
That last thing, I blew half an evening on. It's a sense of empowerment not unlike first learning how to colorize photos.