Back around 1994, I was 22 and had just moved away from my parents' home. I was renting a room in a 3BR house with roommates. We had pastimes like dancing to Deee-Lite, playing TinyMUD, and playing DOOM on a null modem connection with my 386. It turned out that one roommate had pastimes involving a pump shotgun he stored under his bed. But anyways.
I was eager, and knowledgeable enough, to register a unique domain name for the entire household. It wasn't clear how we'd use it, with no permanent Internet presence, and we didn't have any hosting, DNS, or BGP capabilities, but a domain name sure seemed like a nifty thing to have, and it was free. So I aimed to register under .ca.us.
Perhaps I was not feeling creative enough that week, or it was quite difficult to capture the zeitgeist of four completely different college kids sharing a house, but I decided that the best name for us was <street address>-<street name>.san-diego.ca.us. Fictitious example: 1234-main.san-diego.ca.us.
Another curiosity about this particular name was that it may have been on the cusp of standards compliance. In the original DNS specification, a label could not begin with a digit, mainly because of parsing from bare IP addresses, but as you can see, eventually it was permitted, and our domain registration went forward.
It was a real bummer, though, because our household domain name languished, as I argued with my roommates, and we had no means of even setting up email addresses, but for a few shining years I did own a wacky, unique, but very generic street-address-based domain name.
Ha, I also happen to be in the middle of trying to register a .ca.us domain right now! As you say, they can be very plain-looking but unique :)
And (unlike many of the <number>-labs companies) at least there's some logic behind using your physical address for a domain.