First of all, it's actually John Doe, not Joe Doe, and the female equivalent is Jane Doe.
And no, what's-his-name/what's-her-name is by far the most common option for referring to people whose name you can't remember.
The common alternative is to identify the person without using a name at all:
I saw that girl yesterday, that one who hit you with her car. Remember her?
Well did -- what's his name? -- your cousin -- try using a trowel?
In lieu of what's-his-name, among teenagers you will sometimes hear what's-his-face and in more vulgar terms what's-his-fuck.
Another term you will see is So-and-so, but this is used when the name doesn't matter, not when you've forgotten it.
Johnny told me that he heard from so-and-so that you can just fix that with duck tape, actually.
Shelter-half, rain fly, and leanto (or lean-to) are three terms sometimes used as names of a structure as in your picture. Scattered among images on the google-images pages (1,2,3) are some pictures like yours, although for the third term images like yours are infrequent. Also see tarp, tarp tent, and tarpaulin.
Among people who camp in the US, fly or rain fly is the accepted term for the outer layer of a tent-and-fly combination, where the fly serves as a rain shield or additional thermal barrier for the tent. Most multi-season camping tents come with a fly or offer one as an option. Flies for tents typically are shaped to roughly match a given tent (ie are not flat) and are sewn together from pieces of thin nylon fabric, often waterproofed. A tent and fly can be used in several combinations: the tent alone, in mild dry weather; the fly alone, as a quickly-set-up rain or sun or sleeping shelter; or in more-severe weather, used together, with the fly keeping the tent drier and warmer than it would otherwise be.
A tarp, on the other hand, may be made of canvas, nylon, or various combination fabrics (such as rubberized or plasticized nylon). Tarps typically are flat fabric, with grommets along the hems. A shelter-half is a particular kind of fly, such that two shelter-halves together can make up an enclosed tent. Shelter-halves have been common items in surplus stores after various wars, and while (in my opinion) they are practically obsolete, the term shelter-half lives on.
Best Answer
As an alternative to "nameplate", the term plaque /plak/ refers to an object affixed to a wall, door, or other surface that has an inscription or decoration on it. It is often used to identify or commemorate somebody or something.
A door plaque would be affixed to an office door and might have the name and title of the person who occupies the office. It might also identify the room. (For example "Conference Room A" or "Engineering Dept".)
A wall plaque, mounted to a wall near the door, can serve the same purpose.
Q. Are you the head of security? A. That's what the plaque on the door says.