I was playing around with PostgreSQL’s RANK function, and I’ve figured out a decently inexpensive way to accomplish this (and a few other things). 
Relatedly, I was not emotionally prepared to see that the 
Strider has completed more than 12k streets, or that the 
Strider has run in 20 countries.
Also relatedly, I’m realizing how much of a backlog of great #ideas there are - that global update effort really blocked things up for a while. I’m psyched to finally get back to adding/changing things in ways that actually affect everyone’s day-to-day use of the site. 