Alan Aspuru-Guzik and his colleagues recently published the results of a very interesting experiment related to simulating a quantum system using another quantum system. The paper was published in Nature Chemistry and I think it is a very exciting piece of work.
One of the interesting aspects to the work (aside from attacking a very fundamental and important practical problem) is that it uses a very limited simulator to perform a complex task by very intelligently using the simulator in a recursive way (the original idea was published in this Science article in 2005).
This was a problem that we spent quite a bit of time thinking about, and contributed some part to. I am very happy to see it being implemented.
Now if only we could figure out how to do the same sort of thing using our hardware…