Update 1/28/06: Turns out that this DIY water heater was made by Patryk Sielski from Warsaw, Poland. Patryk wrote:
I live in an academic hostel of Warsaw University of Technology. Unfortunately, we don't have hot water in our rooms, it's only in kitchen and toilet outside. This inconvenience caused me to think about hot water. Commercial heaters are to expensive to students, it's also a problem to assemble without temporary cutting off the water. Beside of that, the fuses would be immediately blown.
On the mainland, we do have mixer-taps.