I got teased a bit for bringing a shower cap with me, but I used it to cover my bike seat on rainy nights.  Mind you, it's actually pretty difficult to get a bike seat and your head into a shower cap.  But once I learned to take the seat off the bike first, it got easier. 

That's a good example of how you'd just learn to improvise out on the road.  If you didn't have a nail, you'd use duct tape.  A paper plate might make a good notepad.  You just had to make do with other things, because in Africa you can't always find what you need.  Which is why, in addition to the shower cap, I packed a life-sized inflatable doll. 

Anyway, this picture:  sometimes tensions ran a little high on the Tour.