Yeah, too bad it's not a Discworld book, though.
But yup, in Dark Side of the Sun they used a singularity in a box to assassinate (or attempt to.. I forget) somebody. I don't think that really makes sense but eh?
<edit> By the way, he kind of missed the most important and scary one: nanotechnology. #2 sort of alludes to it, but he doesn't even mention nanotechnology. Anyways, read up on that in the Wikipedia article called
Grey Goo. Grey Goo scares me.