This was an interesting one; it was the power supply for an externally powered USB hub, which, following a loud bang, let out the magic smoke when it was first plugged in. For this one, the smell of dead electronics lasted most of the day. These photos were taken during the autopsy.
This smoke release was so energetic that it did the following to the bottom of the case. And this is one of the best electronic skid marks I have seen in quite a while.