Don't forget gym showers, people. Whether they are gang showers, individual stalls, or steam-filled rooms for 2-4 strapping, muscular men so musky and dimly lit that everything moves in slow motion, gym showers are where gay/straight guys go to turn each other on by showing off their bods. They use gym showers to jerk off, or at least to get a hard-on so they can show how much they don't have a problem with guys seeing their rock hard cocks. Other guys, mostly American men under the age of 25, use them to clean their gym clothes by not stripping down at all.
I use my gym shower for unusual purposes, to rinse off and cleanse my body after working out. I'm an iconoclast, what can I say? I wouldn't rule out using it in a more mundane way, like getting gang-banged by a {insert sport} team.