So my shower is in the basement of the house, which doesn't get any heat and is currently below freezing. There are some hot water pipes in the bathroom itself, but they do little to dispel the cold unless you're right next to them.
Now, I'm unsure why whatever heats the water in the pipes is not connected to the shower, but it's not. Rather, the shower is connected to the tiny water heater by the sink. That water heater is fine for making enough hot water for doing dishes, but it's not enough to make more than a few minutes worth of hot water come out of the shower.
My family is part polar bear. They talk, host mom included, of the joys of taking a jog and then jumping into an icy river. "That river?" I asked, pointing out the window at the one near the house. No, that one's polluted by the beer factory upstream. Ah.
In any case, my delicate nature does approve of jumping into icy rivers, nor does it like taking freezing showers, so I developed the shower ritual.
First, I wash my hair while fully clothed. I wet it over the tub, and then immedietly shut the water off, giving the heater upstairs time to make more hot water. I put in the shampoo, and, since the instructions on the back of the bottle say to leave it in for a few minutes, I read a bit of whatever book I'm working on, holding it out at arm's length so that water doesn't drip on it. I wash my hair first because if the hot water goes out at any point after this, at least my head won't be doused with freezing water.
I quickly rinse the shampoo out, switch the water back off, and then towel-dry my hair. Now it's time to get brrrrr. Off goes the sweater and the rest of whatever layers I happen to be wearing and I lean over the tub and wash my torso. Whatever hot water is not hitting gets goose-bumps from the freezing air. The water gets shut off. You get the idea from here. The bottom bits go, and by then some warm water has accumulated in the tub so that my feet aren't on cold porcelein. I lean against the hot water pipes on the wall to keep my torso warm while I wash the rest of me, then the water gets shut off, I dry off in a hurry and toss my sweats on. I'm still a little damp but at least I'm warm.
The punch line: I've been doing this for the better part of a month. Then, two days ago, I notice my host mother turning a knob on the water heater by the sink. She went to go take a shower, and as soon as I heard the water in the bathroom turn on, I saw the small gas flame that heats the water tank turn into a roaring inferno. After her shower, she turned the knob back.
Before I took a shower this morning, I turned the knob. When I took my shower, hot water came out and didn't stop coming. It was the first hot shower I'd taken since I left the United States.
Victory!