Earlier this year I read a short story or novella in which some corporation produced a minuscule supercomputer-on-a-chip, which was subsequently used to create a simulation. The simulated beings were given a nanofabrication facility with which to experiment, and wound up everting themselves into the real world in some fashion, causing massive destruction.
It felt like it was written in the '90's, but obviously I'm so fuzzy on the details that I can't even turn it up in a Google search. Could have been more recent.