Yes! I live! I was waiting around for any excuse for me to post.
DoF is easy. And it's not a 2.5 function at all. Nor nodes, nor compositing, nor sequence editing.
1. Select your camera.
2. Go into Editing (F9)
3. Hover your cursor anywhere over the Buttons Menu (if you are in Editing mode, you already have Buttons Menu up and ready, I guess I could also say "hover your mouse over the "Camera" tab.)
4. Notice "Focal Distance," hit it to add a "Focal Distance" keyframe.
5. With this newly acquired information, animate as normal. The principle of animating a "Focal Distance" keyframe is the same as any other type -- loc, rot, scale, the whole shebang. ("Focal Distance" is the "DoF Dist" parameter)
6. Make something awesome and post it here because we could really use it
Also, if you don't want to set numerical values or need to focus on an object, you can always type the name of the object in "DoF Obj" and it will automatically focus on that and blur the rest.
Hope this helps!
(Yes! A reason to fire up Blender! Haven't done that it forever!)
BTW: Yes, it does work for lighting, use it in my game experiments all the time. It works for just about everything, texture, color, norm, alpha, etc. I think the coders make it a point to make EVERYTHING animate-able.
"Along with 'Antimatter,' and 'Dark Matter,' we've recently discovered the existence of 'Doesn't Matter,' which appears to have no effect on the universe whatsoever." -The 5th Wave