It turns out that the shower head attaches by a ball joint, so i tried shoving it back on which seemed to work, except that water was still spraying out the back, even more this time, and it popped off again almost immediately. After looking at it a little closer it turned out there were several cracks running lengthwise along the back on the part that was supposed to grip the ball joint. When the water was turned on all the way the pressure would force the bits apart along cracks and it wouldn't be able to grip the joint anymore.
The _easy_ temporary solution to this would be to reduce the water pressure, it worked reasonably well, or at least didn't fly off the pipe, when the flow was only a fraction of the max. However this shower is one of that wonderful kind where there is only a single twisty knob. Starting from zero to about halfway around you get cold water of steadily increasing pressure. After you pass the halfway point the pressure stays the same but the water goes gradually from cold to hot.
So until it gets fixed i can either take cold showers, try to hold the shower head on by force (which i can usually do for about 30 seconds or a minute at a time before the pressure pops it off again and i have to turn the water off, jam the head back on, and turn the shower back on) try to shower under the narrow high pressure stream that gets emitted without the shower head to split the stream and reduce the pressure, or give up and take a bath instead. This morning i did a little bit of the repeatedly reattaching the shower head and using the unmoderated stream straight from the pipe. By the time i was done of course the rest of the bathroom was soaked =P
I saw the manager on my way out of the apartment this morning so i let her know about the issue and she said she'd _try_ to get it fixed today, but that she was rather busy and she might not have time for it right away.
Lots of fun =P