I work in a large university building that hosts physics, chemistry and some more applied technical research, which means that it is great fun to occasionally go down to the cellar where the trash is being collected. Usually there is not much interesting in the electronics bin, but over the years I have brought home, for example, a fully functional TV (720p) and a few magnetic stir plates that are useful for yeast propagation.
Some while ago I picked up the power supply that is pictured above. It looked useful for some home automation project or whatever, and I hoped it would be low-voltage DC, which is most useful in this context. I could not have been more wrong: It turns out it is AC, adjustable up to 5 kV! While I took enough care to not electrocute myself, the multimeter that I used got fried for good.
A look inside reveals some nice manually assembled circuits and the ID of central unit is searchable, confirming this is a high-voltage AC power supply. I have no idea what to do with it now, but I have not brought it back to the bin either. Ideas welcome!